UFO Exit Ambush

While you are Sweeping the Battlescape, the aliens will often remain inside the UFO. Inside the UFO, aliens have many places to hide, and your troops risk getting gunned down every time they stumble blindly into a room. It is therefore usually best to stake a position outside the UFO's outer doors and let the aliens come to you.

Successfully ambushing aliens in this manner requires soldiers with high Reactions; the reaction shots they take will provide good Reaction Training.

The Basics

Arrange your troops with a clear line of fire to the door, and wait. At about turn 20, the aliens in the UFO will start wondering what befell their comrades and leave the UFO. With your soldiers lying in ambush, finger on the trigger, this resembles a turkey shoot more often than not. This is probably the most convenient way of training reactions, and reasonably safe provided you take a few precautions.

How things may go wrong:

• often more than one alien will come through the door in one turn. Your troops will usually kill the first on the spot, but (depending on how good your troops' reactions already are) the second, third, or nth alien will have time to fire it's weapon, possibly killing a soldier.

However: even if an alien gets to shoot, it may still miss; and even if it hits, it may cause little or no damage (at least after the introduction of armor). Also, the chance of too many aliens popping out all at once is directly related to the size of the UFO. So, if you restrict yourself to smaller craft at first, you won't lose many soldiers – while the survivors gain ever more experience, becoming better and better at handling such situations.

• if your troops are assembled in close ranks, this basically is an invitation for the aliens to use grenades, killing one and wounding several of your troops.

However, in the early game only few aliens are carrying grenades; in addition, it still has to get out of the door and face your troops before it can perform the evil deed. Chances are you will catch it before; and once you have flying suits, you'll be safe from grenades anyway.

• if the aliens have Blaster Launchers at their disposal, things may become really really ugly.

In nine out of ten battles, they fail to use it; however, if they do, you're licked. If you don't want to resort to save-and-reload under any circumstances, you better don't camp Battleships.

En Detail

Troop positions

1. The best place is to the side of the UFO door, as far away as possible (but remember that your troops mut be within 20 tiles in order to spot the aliens).
2. Avoid stationing soldiers on both sides, as they may catch each other in a crossfire.
3. Avoid positions where aliens may still see (and shoot at) your troops from inside the UFO.
4. Absolutely avoid placing your troops in front of the door. In addition to risk #3, this will create a mutual surprise situation where the alien gets a guaranteed first shot.

If possible, spread your troops out: troops which are standing shoulder-to-shoulder are very attractiveGreande targets. Flying Suits are excellent for UFO door ambushes: hovering troops are immune to grenades, and since they are firing downward, they can be placed on both sides of the door with little risk of accidentally hitting each other.

The soldiers assaulting this UFO have decided to wait for the aliens to come out. Four shooters are kneeling, facing the UFO's only exit. These soldiers have the highest reaction stats in the squad. It is recommend that only soldiers with good reactions should be used. However, the more soldiers the merrier no matter their reaction level.

The main benefit of having more soldiers is to have reserves, just in case there's a whole bunch of aliens coming out all in one turn. If your high-reaction soldiers have spent their first shots, things may become hairy – this is the situation where the presence of a merely mediocre soldier will still prevent the worst. Besides, only soldiers who are there have any chance of increasing their skill at all.

Before shooting one of the soldiers, an alien must:

• Open the door and step outside (8 TUs)
• Turn to face the target (2 TUs)

The total is at least 10 TUs. For slow aliens like Snakemen, that's a significant fraction of the total TUs, and the loss of 10 TUs often allows a soldier to fire first. Also, aliens do not always start on the square next to the door so they may have used up even more TUs.

The other soldier in the frame isn't a shooter. He's a looter. Looters have nothing to do with increasing anybody's reaction stat and everything to do with increasing X-Com's "bank balance" stat. Looters pick up corpses, stunned aliens, and dropped equipment and carry them somewhere safe, where they won't get destroyed by an explosion. Stunned aliens can optionally be left alone to provide even more reaction training once they recover. The looter can also be used to scan the entryway for any possible movement during some of the more quiet turns.

The Troops

The soldiers lying in ambush should have pretty good reactions to begin with; as a rule of thumb, 45-50 should suffice for the Beginner experience level, while on Superhuman the best rookies money can buy are still at risk. See Alien Stats and Difficulty Levels for the raw data, and Reaction Fire for how it computes.

Decoys

If you're nervous about your troops getting shot, put a tank nearby. HWP's draw fire; aliens prefer to shoot at them over troops. As long as the tank is in the aliens' line of sight, and as close or closer than the troops, the aliens will always shoot at it before the troops. When I train, I keep several tanks on hand, replacing damaged ones with fresh units as they get shot. --Papa Legba 14:09, 28 Nov 2005 (PST)

Smoke Grenades

One way to reduce the likelihood of return fire is to drop a Smoke Grenade outside the door and station your soldiers 10-15 tiles away. Aliens emerging from the UFO will have to walk several squares before they will be able to see your troops, reducing their TUs subtantially, making it much more likely that your troops will be able to fire first. This also blocks the view of aliens within the UFO, making it impossible for them to shoot at your troops from within the craft.

The smoke will thin substantially within 10 or fewer turns; a new Smoke Grenade should be triggered at least that often. The smoke from a Smoke Grenade is much thicker than the moke generated by explosives (Proximity Grenades, Rocket Launchers, etc.) and is much more effective in this role.

Proximity grenades

The square marked with a 'G' is a good place to put a Proximity Grenade. It is a good idea to mine the exit while the shooters are getting into position - in case an alien pops out before you are ready. Once the shooters are ready, the proximity grenade can be destroyed with a normal grenade. If the UFO contains Mutons, you may consider to leave the proximity grenade where it is to soften them up before the reaction shots. Then grab the loot and set another proximity grenade for the next one.

Note: Prox Mines do not give you any experience. More specifically –and oddly– unlike other grenades, they give experience to the unit that makes them explode, not the unit that primes or throws them. So, Experience that might've been gained is basically lost – newbie units (pre Power or Flying Suit) dare not set off their Prox Grenades (which is counter to their purpose), and PS/FS units generally have psi capability and don't need proxies any more. Sure wish they designed Prox Mines differently – Ed.

Which weapon to use?

This depends on how many shots you expect to get, which in turn depends on how many shooters there are, and how good their reactions are. If the number of shooters is small, it is best to use something accurate and powerful to get a quick kill. The Plasma Rifle has the most accurate snapshot in the game, is an excellent reaction weapon, and sufficiently lethal as well.

Laser Pistol

With more deadly weapons, it's often the same ambusher who, time and again, gets to loose the first and only shot. With Laser Pistols, on the other hand, it usually takes several hits to kill even a Floater. This directly translates into more reaction and hit events you can milk from a single alien, hence leading to a greater stat increase. In principle, the standard issue Pistol would be even better, but also opens you to all sorts of logistical issues like bringing, and keeping an eye on, ammunition.

The little time neede per shot means that your soldiers will still get to shoot first against the second and maybe even the third alien; five or six top-of-the-line rookies with Laser Pistols will be able to safely deal with a typical Large Scout's payload of Mutons.

Another benefit is that the Laser pistol is also incapable of penetrating the front armour of a Flying Suit or Power Armor, which makes it possible to set up shooters on both sides of an entrance. However, shit happens, so dont rely on this being safe.

Heavy weapons

Lack of an autoshot mode is not a disadvantage, because reaction shots are always snapshots. The Heavy Cannon does more damage, the Auto Cannon has the larger clip; both offer the chance to kill additional aliens still inside the UFO, or at least hurt them (so any shots they might get off will be more likely to miss your troops). Use of high-explosive ordnance also means that you will destroy much of the loot and gain less experience overall.

The same caveats apply to the use of the Rocket Launcher; in addition, due to the time spent on reloading, it will only provide a safe reaction shot every other turn. But then again, it can be fun to watch.

The Small Launcher

This weapon has the potential to generate many reaction shots - first to put the alien to sleep, and then every time it wakes up. This is bordering on an Exploit. But keep in mind that a stun bomb can do up to 180 stun damage, so it could take tons of medkits to wake up the unconscious target. Maybe it's not so hot a trick - but plenty of fun!

Tips and Tricks

• If you shot down the UFO and the explosion of the UFO Power Source made any holes in the UFO outer hull, you will have to set up ambushes at those locations too in order to avoid aliens circling around behind you.
• Aliens tend to prefer to use the door further west on the Supply Ship.
• Make sure not to stand right outside the door, otherwise you may be at risk of angled fire coming from INSIDE the UFO after the door is opened by the first alien you kill. On a similar note, watch out for door jamming.
• The protruding upper storey of the Supply Ship means that you have to get down on the ground in order to properly watch the door. However, the roof above also means that the aliens cannot throw grenades very far.
• Likewise, the upper storey of a Battleship protects you from grenades as long as your troops are sufficiently far away from the door (five or six tiles, diagonally). On the other hand, there's usually at least one Blaster Launcher on board, which can be so much worse.