He was. I imagine it was because he felt he didn't have much else left.

Sergei was a very strange person in general, honestly. He called some of the more intelligent mutations his "brothers," for some reason; he also liked to insist that machines had feelings that were beyond human understanding. He would tell me that he was glad we were such good friends and had such a healthy, functional relationship immediately before trying to kill me; he commented on how peaceful Russia is before mentioning that he was looking forward to burying me there. It was..."interesting" is a good word for it, if a bit mild.