if china will ban it they will ban the mining activity too, which mean that the diff will decrease dramatically, and miners will have an easy time making profit for a long time
you can't simply replenish 70'% of the network in a short time, the price i think it will not tank so much, because panic buyers will be all over the price when the value will tank
Panic buyers did not manage to keep the price up when the price started tanking to 200 after the last rally.
If there is real blood on the street, those buyers will rather be panic sellers. Smart money will still buy though.