What would you have done as a passenger?

ChaseZ

This is clearly the more important piece of information shared.

And I don't think you could have done anything different. By the time she would have reacted in some way you you yelling instructions at the same time as the near miss is taking place her instincts likely would have been to mash one pedal or the other, neither of which would accomplish a slow controlled movement out of harms path - and there very likely wouldn't have been the time for that anyhow.

The real answer to what you should have done however is to size up the situation then pull out your CCW and shoot the driver through his windshield hitting his right shoulder which would cause him to pull the steering wheel correcting the uncontrolled slide of his car and resulting in a harmless fishtail down the road with a large gap between his vehicle and any other traffic, coming to a gentle stop near the opposite curb.

You could then nonchalantly go ahead your day with full and quiet confidence that you saved the world from the needless fate of yet another careening, ill-advised mustang.

Thanks, we owe you one!