desent movie lowsey ending spoiler

Thought movie Was Entertaining. Liked that the siren wasn't after the dudes. Well in a sexual way. This movie sure wasn't ordinary. Pleasing, surprising, but had crapy ending. Why put yourself in danger to go after someone you care about to kill that person later. Doesn't make any since. The movie would have been better if they leave out the last minute.
Go ahead, struggle, i'll just make it hurt worse