Unsettling car park

I had reason to have my insides poked about with today, so parked in the striking looking car park 2 at the hospital. As ever, I had to go right up to the top to find a space. I had a little time in hand so sat in my car for a few minutes. Every now and then, the car shuddered and I realised the car park was MOVING!
Happily, my insides seem fine.