Just saw that "huge" move down, was expecting it to at least test that giant buy wall at 17.2k I'm seeing at my exchanges but it didn't even survive 15 minutes below 18k. Guess they're going to need to bounce off 18k a few more times before the buyers let go of some ground. Meanwhile, I see a lot of gains in alts, guess people are spreading out some of that BTC in alts, so seems to be less about people selling BTC, more about buying up alts with BTC?
Was also expecting to see low $17K prices if $18K was broken as well, but seems price might bounce around in an indecisive way for a little while. I think you're right that no-ones really "dumping" BTC at the moment. I don't see people selling BTC for fiat, as price is still trading sideways, instead they are diversifying into alts by the looks of it. The charts suggest it's not the worst idea either.