Linda and I have ridden for five years and had a tip over once each year. Fortunately, she has not had any serious injuries, other than some elbow scrapes and soreness. I did have some the rib injuries last year. The closest call for her was two years ago when we tipped over to the left and the rear crashbar actually pinched her shoe off her foot. This one could have easily crushed her foot.
There is no real good way to get off in a tip over, but to me, leaving your foot on the rear peg/foot board would not be the best. On a 1st gen, which will go all the way to the ground. the passenger's 1st point of contact will be their elbow and shoulder. The best way may be to swing their leg out as wide as they can and try to step away from the bike and as they fall toward ground, try to roll.
Then again, you can practice, practice, practice.
RandyA