The point about panic is a good one. A happy rabbit navigates at top speed with ease, and it's nothing to worry about. But if a rabbit goes into panic mode, they can get seriously hurt. You can tell the difference between panic and fun: when it's a fear response, he will flatten hishindquarters, ears erect and head up. He may quiver a bit, then will take off at top speed. He won't respond to voices, and will run blindly, then stop abruptly in the same position, then run again. His eyes will be wide and wild-looking, with no recognition.
A happy rabbit will zoom around, in and out of things, with eyes normal and ears either up or flat back. Often the racing will be interspersed with twitchy "binkies" or aerial maneuvers.
I've seen both, and the first one scares the livin' out of me. Bub used to have a problem with crows, and panicked every time he heard one. The most important thing was NOT to chase him, but to kneel down and call his name over and over in a high, gentle voice until something penetrated his little brain. He was known to hit his head and crash into things, even though his eyesight is normal--he was just beyond rational thought.
Your case sounds like classic happy bunny, but I just thought I'd add the info so people know the difference between panic and bunny 500.
Rose