Hormones.
He was likely doing the buzzing noise himself, almost like a honking - its classic hormonal behaviour at sexual maturity and the fact he had clear testicles says he's at that age. Surprised they didnt suggest neutering or anything.
The skittishness could of been binkying/ mini bunny500s as the owners clearly knew nothing about rabbits.
^^^^^^^^^^^ That
'I thought there might be a fly in his ear or something...'
*Wipes away tears of laughter*
Hilarious stuff. :lol::lol::lol: But wouldn't you, I mean, Google 'Basics of rabbit care' or something upon bringing your rabbit home, even if it was an impulse buy? They must be really embarrassed watching that back.