This also confused me. There were clearly more nights. But right now, and specifically the healer. Someone who knows the Master well, sensing an important role for the Master, strikes?
P.S. And if the Sheriff really has no more marks, it's unclear why she didn't wait one night to kill two people and get a free target for the kill?
Added after 33 seconds
The Wizard is formally dead; ND won't work on him this night.