skyliner1004 said:
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what are the chances of damage to the bike on tipping over while clipped in? .
Very little. Don't worry about it. Usually the worst that happens is levers moved or scratched a little, or bar tape damages.
BTW, the OP's crash could have happened with toe straps, or even plain pedals. A sudden washout like that can put you down in a fraction of a second. Actually, from his description it sounds like he did get at least his right foot out, not in time to prevent a fall, but in time to get his leg in the way of the chainring (you can't do that while clipped in). So, ironically, he might have suffered less if he hadn't gotten out at all.
I was un-clipped on both pedals ready to get off
Most experienced riders get in the habit of unclipping only one pedal, and always the same side, until they're fully stopped. That way, the whole motion becomes instinctive, including leaning the bike the right way so you don't fall toward the clipped side. Leaving one foot in also gives you one secure place to stand on the bike, so you're not balanced on the seat with no lower anchor point. If you're not going to get off the bike you leave the other foot clipped in and stand on one foot, so you're ready to take off again.