That three-wolf level had me stuck for ages! I found after a while that knocking the wolf down and kicking it (shift+left mouse, then left mouse I think) and then stabbing it with the knife (crouch+left mouse while crouched over it) is fairly reliable. They might roll away if you don't get there fast enough, but it works eventually.
PS. This trick is worth 200 points if you can kill a rabbit with it!