Phoenix Point
47 Achievements
GOG
Survivor
Survive an ambush mission
26.8%
How to unlock the Survivor achievement in Phoenix Point - Definitive Guide
WhyattThrash
TrueAchievements
TrueAchievements
Ambush missions have a chance of occurring any time you explore an unknown "event" location. Instead of getting some useful event or a blank space, there's a chance of it being an ambush. The objective of ambush missions is to survive for a few rounds, and then evacuate your soldiers.
While it's supposedly possible for ambush missions to occur on any difficulty, I've only ever seen them on the easiest (Rookie) difficulty. Two full playthroughs of Veteran and Legend without seeing a single ambush, and on Rookie they happen constantly.
So if you've completed everything else and are just missing the ambush mission, fire up a new game on Rookie and go exploring. The rumour says ambush missions are more likely with lone, "naked" soldiers, but I've gotten more of them with a full ship of maxed out fully geared teams. It seems the only real RNG manipulator is that it needs to be on the lowest difficulty. YMMV but those are my experiences.
While it's supposedly possible for ambush missions to occur on any difficulty, I've only ever seen them on the easiest (Rookie) difficulty. Two full playthroughs of Veteran and Legend without seeing a single ambush, and on Rookie they happen constantly.
So if you've completed everything else and are just missing the ambush mission, fire up a new game on Rookie and go exploring. The rumour says ambush missions are more likely with lone, "naked" soldiers, but I've gotten more of them with a full ship of maxed out fully geared teams. It seems the only real RNG manipulator is that it needs to be on the lowest difficulty. YMMV but those are my experiences.