Scaring the Dementor may have saved his bacon. Blackmailing someone is a positive utility move. Blackmailing someone who seriously believes they can destroy hundreds of unkillable soul-eating monsters, and backs that up is a move with totally unknown utility, possibly very, very negative.
Scaring the Dementor may have saved his bacon. Blackmailing someone is a positive utility move. Blackmailing someone who seriously believes they can destroy hundreds of unkillable soul-eating monsters, and backs that up is a move with totally unknown utility, possibly very, very negative.