Rape is a felony. In my state you can use deadly force to stop or prevent a felony on you or anyone else.
Tell them to stop. If they don’t, make them stop. Of course if there are a hundred of them, you better have good judgement on not only who gets killed first, but next. Although (I haven’t seen the video) I imagine it is a bunch of younger college-types, and more like sheeple than a hard-core mob. I would guess many of the people in the crowd thought it was wrong, but too afraid to say anything, or didn’t want to ruin the “fun”.
I would call 911 first in a mob like that, as you are yelling at them to stop.
Of course make sure you have your facts straight. Some of the girls today might testify “It wasn’t gang rape, they said if I would “do” at least 4 guys I’d get a hundred bucks!”
If that would be the case, Hillary best turn the Mystery Machine around and not campaign in your state at all.
If there is a forced rape in progress, and the person intervening is 80, I’d say a shot to the head at close range. You can’t risk trying to scare off a young violent felon so nuts he is raping a woman in front of witnesses. That is mad-dog crazy. At 80, I would not feel obliged to reason with a mad dog committing a rape. Shot to the head. Stop the forcible rape in progress, the best and fastest way possible. Bang.