I had a loop of chain at the center of the head of a metal bed, secured by both a padlock and combination lock so that opening either one would release it. My feet were secured to the bedposts and to each other (about 60 cm.) so I couldn't move them very far. Not only did I have a timer on a light but also an ice cup with a padlock and handcuff key was directly over my upper chest. After cuffing my hands in the chain loop, cold drops starting hitting my chest in about ten minutes.
After 45 or 50 minutes something big hit my chest followed in a few minutes by something smaller. These were the two keys, but they had bounced off my chest and I could neither see or feel them. The light was, of course, dim since if I could see the combination lock, that would defeat the pupose. When the light came on, neither key was so far away I couldn't have slid it up to my hands with my back, shoulders, or upper arms with some effort.
I was only able to do that one time when the padlock key hit my chest and stayed there. Don't think I'll be doing the ice cup thing on the bed again, too many things to go wrong.