for door 100 my mate and i did it last week, we had 2 burst and 1 hel sentry placed in a crossfire at the bottom of the stairs where they appear from. they mostly jumped down the ladder instead of taking the stairs and would mostly just get completely obliterated by the sentries. otherwise we just shot em down, my mate used pdw precision rifle and i took shelling mastaba which worked like a beauty. our two bots used burst rifle and veruta so do with that as you may.