Did Nadine

I thought it was accidental, because she seemed a bit naive about drugs, and she wanted to take the same dose as everyone else, even though she probably had not built up a tolerance.

But at the end of the movie, when Bob is thinking to himself, he indicates that Nadine committed suicide. And she did seem pretty miserable just before she died.

Yeah, accidental. I think she shot the entire container of dilaudid. She had palmed it so they didn't even know she had more.

At first I thought it was suicide because she said she'll show them before they left, but then I realized it was accidental and she just wanted to show them she could shoot the same as them.

Poorly Lived and Poorly Died, Poorly Buried and No One Cried

I've seen this film a few times and I believe it was an accident. She says she will show them all. I think she was humiliated by Bob when the robbery was messed up and it was her fault. She had the lowest tolerance and all the other crew were long time junkies. She wanted to prove she could shoot dillaudid, which she couldn't and died.