This mission for the Nemesis has been buggy for many years. The issue is that the npcs you gather along the way tend to bug out at the end of the mission. But even on the way during the mission the mission tends to bug. This is from my Girlfriend since she asked me to help with this.so to sum it up for youi
1st attempt: solo. red winter fine (2 of the villains left which seems normal). war room: every npc hero broken, neme and 4 other villains auto agro
2nd attempt: party with 1 other player. red winter stayed in full (not sure if bugged or intended for party of players). war room: all but one npc heroes broke. 3 villains auto agro along with neme
next here.
and i know that because sometimes red winter doesn't always lose 2 of its members in my solo runs, and the war room seems to be completely random as to which npcs will help you fight and how many of the villains other than the neme will auto agro. sometimes only 1 villain agroes sometimes all of them
plus npcs heroes don't always activate immediately upon rescuing them
i have to leave the room and return to it before they'll activate
Comments
You do need to defeat all the villains and rescue all the incapacitated soldiers, but you can avoid rescuing every hero except for the guy who hops into the power armor. If you save him last, you can rush to the door to the final area, and open it before he gets in the suit. It is possible to defeat the nemesis before the cut scene where he dons the armor. Even if interrupted by that, you can easily defeat the nemesis before he walks into the room. Once he enters the room a villain spawns, but you can leave the instance at that point because the mission completes when the nemesis is defeated.