Ok I do understand the love of making gamers squirm and beg in the face of sheer destruction they only have the slightest of chances of surviving. However this thread isnt about what we do to make sure nothing progresses to that stage.
Its about what we do when and if we do get there.
Whats more, is that although it is perfectly reasonable to come to a 'gentlemens agreement' over the continued existance or behavior of the psyker, this threads objective was really more to find a mechanical way to accomplish the same sorts of things, that way psykers know from the start what they can and cant do and makes things far more agreeable later in the game.

on a final note :P may I steal that campaign idea? Although I would suspect Genestealers to pick a more inhabited or vital point to infiltrate (unless said facility was indeed vital) its still a brilliant Idea for a one off adventure.