If you’re already afraid of hospital stays — and really, who isn’t? — watching The Good Nurse is going to be an especially scary experience.

The thing you probably want to know most when watching this true crime Netflix movie is why former nurse and serial killer Charlie Cullen (Eddie Redmayne), currently serving multiple life sentences, murdered at least twenty-nine patients by spiking random IV bags in the supplies cabinet with overdoses of medications like insulin or digoxin, soon to kill whatever unlucky ailing person got hooked up to one of the spiked bags.

But it seems Cullen never said definitely why he did it. It’s possible he didn’t know why himself. In the film, all he states is, “Because nobody stopped me.” And that’s the admirable angle the film takes to redirect your attention throughout to another question: why so many different hospital authorities never investigated or reported Cullen.