I fly the triple. Most likely scenario is that they needed over 250 kts at max weight flying clean. The FMC called for 250 since it was below 10000’ and the PF called for flaps up and the jet tried to maintain 250. That will get you a great view of the “zipper”. Had an F/O try that on me out of HKG. Luckily I caught myself as I was about to move the flap handle.
BTW, we all hand fly the 777 up to cruise (or at least above FL250) and on approach. I usually do it sooner on arrival if I know the PM is good with doing a slight bit of work. It’s never an issue if briefed.