Look in comments (whitespace collector is still another timeline)

The collector is able to look into other timelines
(Using a dimensional diamond)

He could go to them but refuses to, because if he does go just his presence could cause an incident similar to whitespace collector

"and y'know what I learned?"

...

"That I can't trust either of you. Now get out"

"How? We're stuck in a white void?"

They had remade a few universes by that point

Remember, this is AFTER whitespace collector