So I finished the main quest and convinced Dr. Klein etc to work for me (also tried this with killing them but it still happens) and the quest updates to "Leave the Think Tank". Every time I try to do so the game crashes; I assume while trying to start up the slideshow. I'm pretty much stuck now.

I have the exact same problem. Tried completing it in different ways aswell but crashes when trying to leave the tank.

Ah ha! Are you playing it in a window? I was and just changed it to full screen and works fine for me. Let me know if that helps.

No I was in Fullscreen, tried going windowed mode though just now to see if that might do it but no luck. Playing fullscreen 1920x1080, graphics drivers are up to date etc

Well the only other thing I tried differently was to complete it by winning over all 4 doctors and then confronting Klein. So no idea if it was that or just that I am no using full screen.

I tried it that way originally, then I tried just killing them but alas neither worked. It's gotta be something graphical or audio.

Got through it. Apparently I was hungry.