The [very experienced] rotorwing pilot I was flying with was really squeamish that high, and asked me to get back down close to the ground as soon as I'd had my look around
Some helo pilots seem to be afraid of height and get edgy if above 1,500, source of worry is a main transmission failure they said, had one such US Army graduate so took him up to 16,000, we regularly flew at 10,000 on a transit. When doing my training on the Huey it was standard practice to go to 14,000 for a vortex ring demonstration, being military we wore parachutes for the exercise. One military required parachutes above 5,000 in helos, which was a nod towards transmission failures I guess.