["Well, shit" is probably the correct response, though Viktor doesn't say as much. He still looks like he might be sick at the thought of it, though there's some effort to steel himself. Jesper's words might be appreciated if not for the fact that Viktor can't not assign himself some amount of blame for this.]

It is my fault. I shouldn't have given them the opportunity in the first place.

[Shouldn't have built it in the first place, even if the more logical part of him knows it would mean resigning himself to death.]

It was foolish, to think I could build it and destroy it without anyone knowing, or watching. They raided my laboratory when I was in recovery.

[So it was calculated, on their part.]