Apparently it was at about a bit more than 10,000 odd feet and it was not the first flight of that aircraft up to that spot. Not saying it was the same operator at the helm though.
Watching the video the aircraft is still OGE when it tops out on N1. Maybe it did just have IGE performance. At that altitude in a Jet Banger you would need all your ducks in a row.
Looking at a bit of historic METAR data from nearby it could have been as bad as ISA +20?
Another trap when operating at those altitudes is that you need to check that max N1 is available with a "topping check". Not everybody does them to see and it can certainly rip your nightie.
Most FCU's are slightly out and a missing .5% will end your day thanks to the exponential curve.
2°41'55.97"N 76°52'18.59"W if you are interested. There seems to be a road or track of some sort up there.
At least they walked away - luck.