I usually wear a leg strap when I'm in my electric chair, but decided not to one day because I was at home and didn't think it necessary.
I notice my chair pulling to the left: my foot is wedged behind the caster. I had someone there who also couldn't free it, it was tightly wedged in. I wasn't sure how much pressure was being delivered so I wound up calling 911. It took three strong guys to free the foot. It took them about a minute. (Might have had a glass of wine earlier).
My foot was a bit bruised, but the only real damage was to my ego. It was embarrassing to sit there looking like someone who can't even drive a chair, and they send over a full fire truck with lights flashing and an ambulance.