Depends on how and why and who it happened! If Turq killed Vincent Yuri would be mostly zen with it but he would have to do that thing where he really just wants to just rush over and hug Vincent or make him feel better and doesn't because he knows that is not necessarily what VINCENT wants or needs.

If someone else killed Vincent Yuri would be pissed as hell :'D Probably not enough to shank someone but VERY VERY PISSED OFF.

If Flynn kills Vincent Yuri would. That would fuck him up. Potentially significantly.

When Vincent offered to Flynn to let him maim him was he AWARE of how much that would fuck Yuri up?