i don't mind closed spaces so can only imagine how difficult this is for you.
take the ear plugs. i keep my eyes closed. i also ask for support for under my arms and knees. add a blanket for warmth is that helps.

i pretend the chirping are birds in a forest with sun shining thru the trees. and that there's a nice bubbling stream.

sometimes breathing exercises (like having a baby) helps.
there's no getting around it that it's uncomfortable.
take your own medication if it will help you.

i had to get thru my own today and my pain made it very uncomfortable.
there are open mri machines, or partially open machines. you might ask your dr about them.