I'd like to point out that this isn't a random challenge, but in fact a specifically chosen challenge.
/nitpicking
Anywho, a similar challenge was done in the team challenges arranged by Shock last year:
(Ben's vid, not mine)
I'm pretty sure I've done it at around this speed too, because of having to get rid of most/all of the ice blocks in preparation for the flap, and once you've been doing it for a couple of hours, you can do it pretty fast!