She was only 21. I'd like to think that I've always been pretty streetwise, but even I made a lot of mistakes at that age.
People should realise that blackmail is a a crime just below murder and akin to kidnapping. Getting involved with it, means you are descending to the law of the jungle. He might have been facing 5-10 years in jail and there is always the risk that the blackmailer would come back for more.
Sure she was young, but there are many obvious dangers that any adult should avoid - walking in front of train, jumping off cliffs, playing Russian roulette.
I don,t condone violence , but a slap round the head might have been more appropriate than sticking a knife in the girl and setting her on fire,,,
Slapping her was the cause of the whole situation. In fact there is only two ways of stopping a kidnapper, calling the police and what happened here. Obviously he had reason to doubt the police would help.