BioShock Infinite's Combat Design Director and AI Lead leave Irrational for Microsoft

[Kresnik]

Didn't someone leave Irrational recently to work at Naughty Dog?

http://www.joystiq.com/2012/08/13/nate-wells-leaves-irrational-games-for-naughty-dog/

I wonder what Bioshock Infinite is doing to them. Although in this industry, I suppose stuff like this is hardly surprising / the end of the world.