It wasn't expecting violence, probably thought the anon will play with it or something, and then the cut happened fast (and clean cuts hurt less than you expect). The little thing is now in the process of realizing it's been killed. In the next few second you can expect it to go from surprise, through shock(as the pain kicks in), to dead.
No... That was part of a pool, before... The guy cuts it, then heal the yukkuri with some orange juice. Except he put the "foot" backward, which means that the yukkuri moved backward instead of moving forward.