So he tied you in a basement to a metal bed and left you there unmonitored overnight?
Let me guess: is the basement also damp and cold?
Sounds to me like your dominant needs a lesson in safe bdsm practices.
Imho it is eaither a matter of ignorance or criminal negligence, when it comes to restraining someone and then leaving them unmonitored like you have described.
One should have being safe in the forefront of one's bdsm practices; one after all is taking responsiblity for the life of another human being afterall.