Not unless the police have some sort of teleporter technology so they can arrive before the victim is brutally penetrated by her assailant.
Are you seriously trying to suggest it's better to allow a woman to be raped than to wound or kill her attacker to prevent it?
Okay, let's say the rapist has a gun too and he threatens to take the woman's life if you interfere. That's not exactly an unlikely turn of events considering that you're suggesting that you'll have a gun on you at the time, so why shouldn't he?
If no one had a gun, then no one would have to die or be wounded at all. If you got a bunch of people together and forcably removed him, restrained him and called the police, maybe then no one would need to even be harmed at all.
Or would you rather just shoot him to make it a bit easier?
Inflicting pain, suffering or even death on another person irregardless of what wrong they have been percieved to have committed, is just immoral and nonsensical to the extreme because there is always an alternative. In going and shooting the rapist, or any person committing wrong, you descend to the moral level of the villain in that circumstance.
Call that "soppy prattle" or "irrational" if you wish.
Personally, I think the world could do with a whole lot less rationality at times and a whole lot more "soppy prattle".