xela: Somehow this move order feels most natural, but I think white can also live with at . I can't come up with a reason why either move order would be better than the other.
tapir: White can get a second eye in gote at b so the aim of the sequence on the edge should just be to make an eye in sente.
Anonymous: Black doesn't cut with 4. What will happen now?
xela: can't escape, due to a shortage of liberties. See next diagram.