An MRI machine

I want so much to know what it looks like from the inside. The inside of the tube, I mean - the actual inside is probably a lot of wires and chips and stuff.

And why they keep sliding you up and down inside it. Like and elevator, lying down. All the way up, and then stopping at five floors before coming to a standstill.

And how come the noise keeps coming and going and changing in rhythm. Is it intentional, like the flashing lights in an EEG?

Who can tell me?