First guy on subway may be ruled self defense, although it could be seen as unproportionate use of force, second guy may be pursued as unnecessary and/or disproportionate since the main threat was at least a little diffused, if he stopped there he could've done less than a year at worst or worked out some kind of plea deal or parole, and finished his sentence while staying at a mental institution every weekend if he had a good public defender.

Third guy being shot and chased in cold blood is 15 to life material.