It’s kind of like if you tried to “pause” a game of chess. It’s possible, but fragmenting the experience completely destroys the experience achieved by the whole.
As Dream Theater songs go, it’s really cool, but it’s not hard to play after just a few hours of practice. If I had to guess the difficulty per instrument, it’d be:
Vocals: 0/10
Bass: 4/10
Keys: 4/10
Keyboard solos: 5/10
Drums: 7.5/10
Guitar: 5/10
Guitar solos: 8/10
Ninja edit for clarification: I only learned the bass part. I’m just guessing for the rest based on how difficult the bass was.