I think there is minority of folks who would and have assisted officers in need.
The 3%, the non-sheeple, the ones who don't stand there like deer in the headlights, do jump in. Just the other night, an episode rerun of COPS was on, young officer outnumbered in a neighborhood domestic violence call, was "backed up" by two citizens that were not going to let the "moment" escalate at the officer's expense.
The sheer fact that a "lone" LEO, was now being backed up by two upstanding citizens worked, and the growing mob backed down.
Those precious minutes meant a lot, until more officers arrived, and the young officer thanked them for their help.
After all, "Who are the militia? Are they not ourselves? (Tench Coxe, The Pennsylvania Gazette, Feb. 20, 1788.)
Sadly, it is usually only the 3%.