I got into an MRI once, a while ago. Iirc the most alarming aspect of the sounds was that they gave the impression of massive objects spinning, whirring, and moving rather fast around you.
Modern CT scanners, at high rate acquisition modes (like ECG-gated cardiac imaging), spin ridiculously large masses (tube one side + detector on the other) at ridiculously large speeds without killing anyone.
In contrast, MRIs are like the ultimate trance build-up.