"corrections" are never big or epic or anything, they are always logical and properly sized.
what you see is usually a dump and a lot of FUD and you can't really generalize all of the dumps the say way. each of them are different and happen under very different circumstances.

for example this last one started as a simple correction. price went down from $49xx to $4400-$4500 which was less than a 10% correction and everything was perfectly fine, then the China crap started and price went down to $3800-$4000 and they kept attacking bitcoin. and the JP Morgan "bitcoin is fraud" was the last straw.

none of this 30%+ drop ever happened in 20 minutes though you are confusing bitcoin with a pump and dump altcoin. it took a lot of FUD and a couple of weeks to reach that big a dip!