Impossible to say for sure but if I accept that I know that this person is about to be killed and my actions in killing their assailant would definitely save this person's life, I hope I would save them.
The reality is probably closer to "see what's happening, have the initial instinct to help, dilly-dally about whether I would be prosecuted for murder in the assailant's stead, wonder if I put my own life at risk by intervening, talk myself out of action due to selfishness, chastise myself for being so selfish, decide to help but discover in the meantime that the person I was going to save had been killed, spend the rest of my life regretting my indecision."
The reality is probably closer to "see what's happening, have the initial instinct to help, dilly-dally about whether I would be prosecuted for murder in the assailant's stead, wonder if I put my own life at risk by intervening, talk myself out of action due to selfishness, chastise myself for being so selfish, decide to help but discover in the meantime that the person I was going to save had been killed, spend the rest of my life regretting my indecision."
![Undecided Undecided](https://atheistforums.org/images/smilies/undecided.gif)
Teenaged X-Files obsession + Bermuda Triangle episode + Self-led school research project = Atheist.