The G-virus was Birkin's life's work. He cared about that damn virus more than he cared about most people; it's the reason he didn't leave Umbrella with me.

He wouldn't act like this if he knew the mutation was caused by the G-virus. The problem, I imagine, is that I don't know whether it was caused by that particular strain or not.

[Birkin is...very deliberately stepping back from the person with the gun, for what it's worth, hands raised awkwardly to about shoulder-level like he's at least making an attempt to surrender; when he laughs it's more like nervous tittering, and when he speaks it's somewhere between the anxiousness of someone who really doesn't want to die and the resignation of someone who knows he's probably about to.

"You did... Well, you did warn me, I guess..."]