First, the higher the C rating the heaver and more expensive a cell will be.
Second, my guess-
10C would be over 50 amps and I don't recall the P2s drawing that much.
This plus the fact they're not intended to be used anywhere else means they have no reason to publish this [C-rating].
The few places I've seen the "C" rating stated for our batteries, it has been 10C. Without rehashing N017RW's math above, it means our little battery, at a 10C or 52Ah discharge rate, would be depleted after about 6 minutes, probably ruined and pretty darn warm, too. These are all white-paper numbers and often differ somewhat from real-life. YMMV