Four man team - Ranger, Grenadier, Sharpshooter, Specialist. We advance and come across a lone Advent Soldier and Officer. What? Our mission is to Skulljack an Officer? How fortuitous! My Sharpshooter (Geralt of Rivia) headshots the soldier, leaving his brains splattered across a tree. The officer scampers for cover...directly into the path of my waiting Specialist, who Skulljacks the fuck out of him. She wipes the blade off, information acquired - mission accomplished, right?
Wrong.
As I plan to move forward further past the train, suddenly out of nowhere a fucking alien appears right next to my (previously still concealed) Ranger! Fuck! Suddenly my entire team is flanked by this Codex thing. But it's okay, we can salvage this. The Grenadier blows up its cover and takes a chunk of its health...WHAT IT CLONED ITSELF? FUCK YOU, ALIENS. Things get out of hand. My Ranger takes out the original Codex with a shotgun blast, but Codex #2 disables three of my team's weapons, leaving them out of ammo. But it's okay, we can recover...except another fucking squad of aliens shows up - and this one includes a fucking FORMER THIN MAN ARE YOU FUCKING KIDDING ME.
My team manages to hold it together, but barely just. My Ranger says "Ammo? Where I'm going I don't need ammo!" and slashes the fuck out of the Codex #2. Except it clones itself again, but this time so far away the clone is out of the battle for at least a turn. Which my team needs. My heavy uses her auto-reload (thank fuck for that perk) and wipes out Codex #2. My sniper has to get down and reload, unfortunately, but my Specialist is able to take out one of the Advent soldiers. However, she gets royally fucked by the Advent Stun Lancer and is stunned, while the Viper misses its shot. Despite being taken off guard, my team recovers (because they're the resistance, humanity's last hope) and easily takes out the Stun Lancer. Unfortunately, the Viper has great cover, so the sniper has no luck and the Ranger has to move around to get in a better position to Slash. And this is when Codex #3 shows up and tries to mindfuck my Specialist...but no dice. I use my flashbang to disorient the Viper and keep it out of commission while my Specialist puts her assault rifle into the Codex's mouth and blows its brains out at point blank range. Codex finally down - mission actually accomplished.
Now we just have the Viper left. I move my Specialist up the train to try and flank it, while my Ranger gets into position to Slash it. My Sharpshooter takes up a better sniping spot...and then the Viper runs away. Fuck. Scaredy shit. It's okay, I'll just send my Ranger up to follow it...
...to discover its joined a squad of a Sectoid and two more Advent Troopers.
Fuck.
My Specialist is boned. The pod scatters to the wrong side of the train - she's now surrounded and none of the rest of my team can get to her. Even if she retreats, she's going to be able to be flanked. Four against one - not good odds. But she has a high shot chance against the Viper - with a 50% crit chance because of flanking. With a crit, she can kill it and maybe, just maybe, she might walk away from the mission. She hits the Viper...but it doesn't do enough. It still stands. The Specialist bravely fights off a poison cloud from the Viper, but an Advent Trooper rolls up behind her and puts two in her chest, one in her head. My Specialist is gone, despite succeeded in both Skulljacking an officer and killing the Codex herself. On top of that, the Sectoid resurrects another Advent trooper as a zombie, and my Ranger panicks due to watching the Specialist die (she was already Shaken from a previous mission).
In the span of one turn, my team goes from 4 against 1 to 5 against 2. This mission has gone from close success to likely failure.
The Grenadier and Sharpshooter team up and take out the zombie - with all their special ammo expended, they have to take the easy kill. And then it goes from bad to worse as the Viper tongues my Grenadier and binds her up. The Advent Trooper on one side of the train goes into Overwatch - the other Advent Trooper takes pot shots at my panicked Ranger, and the Sectoid just scampers around laughing as it looks like the resistance is all but finished. But my team doesn't go down without a fight. First - Geralt, Sharpshooter Extraordinaire, makes a miracle shot from one side of the train to the other - he threads the needle and kills the Viper, freeing my Grenadier. Second - the Grenadier bounces back immediately and delivers a gatling gun strike with extreme prejudice to the overwatch Trooper, blowing him to smithereens. Third - my Ranger recovers from panic and dashes forward, slicing the other Advent Trooper into two halves.
The tables have turned again. It's 3 pissed off resistance soldiers versus one fucked Sectoid.
The Sectoid doesn't go out lightly. It mind controls my Ranger (who was Shaken, and now after panicking and being mind controlled will probably spend the rest of her life gibbering in a mental hospital) and sends her after my Grenadier. She takes the sword slash like a champ, but between her gatling gun and Geralt's rifle, the Sectoid goes down and we're able to save the Ranger from the grip of mind control.
My team came back harried - our first loss, two gravely wounded soldiers...but we won. We beat those alien bastards.