I revisited the flight data and if flies below 13,000 ft until it finished the drawing. Then it rose to 41,000 ft and increased the speed from ~200 knots to somewhat over 500.
It blows my mind to think that an 747 is allowed to use the uncontrolled airspace as if it were a Cessna.
Ah! This explains the 2:40 time for the drawing. Just eyeballing it, I guesstimated an hour, but I was assuming a constant flight speed. So if it was flying at ~200 for the drawing and ~500 otherwise, that would account for it. Thanks!
Might have been a bit of a trip to fly in your Cessna and see a 747 flying down there though.