Walking away from a fight while everyone yells “do something” takes more strength than swinging.

A crowd shouting for something turns a physical situation into a social one, and the pressure is real rather than imaginary. Leaving while they watch costs you standing in that moment and nothing afterwards, which is the reverse of how it feels. Strength here is a matter of what you can decline while being called soft.

Decide beforehand what you will not be talked into, because the moment itself is a poor place to work it out. Walk without explaining. The people whose opinion actually matters to you will not be in that circle.