Correction:Fitzgerald wanted the bonus for staying with Glass. He was going to smother him, but was caught by Hawk. Once he killed Hawk he was able to convince Bridger that they should leave. He had no reason to kill Glass at this point. He no longer needed to stay, and there is no reason to think that the decision to leave him there would have any consequences. Everyone had assumed it was merely a matter of time until Glass died. Regardless, it is based on true events, and this was the decision made in reality.
Correction: Fitzgerald wanted the bonus for staying with Glass. He was going to smother him, but was caught by Hawk. Once he killed Hawk he was able to convince Bridger that they should leave. He had no reason to kill Glass at this point. He no longer needed to stay, and there is no reason to think that the decision to leave him there would have any consequences. Everyone had assumed it was merely a matter of time until Glass died. Regardless, it is based on true events, and this was the decision made in reality.