What would you do in this situation?

In this order:
“Wife take him and get in the car now!”
Me: walk right up punch him directly in the throat….he gasp…I take my right hand and bring his face toward my knee which is in turn coming up for destructive contact to his nose/teeth……then slam him to ground and bash his face into the pavement 3 times. Most situations like this, or similar experiences I have had will NOT result in people jumping in because most in general will just stand by and watch not wanting to engage especially if you have a psychotic demeanor about you. I like my chances

You're an idiot then.

"Wife, clearly we're in a dangerous situation, so take the child and you two, unaccompanied and unprotected, make your way as best as you can to the car where you will then have no idea when and if I'll return and possibly not be able to contact me as I might get beaten to a pulp and/or arrested"

If you have a wife and kid your first responsibility is to protect your wife and kid and get them out of a dangerous situation as safely and quickly as possible. Trying to kick the dude's *** may be satisfying, but it's also ******* selfish.