I should have expected that. If the humans can kinda do it, why can't Suriel.(referring to the above question)
Suriel did it already. It's how the Great Elders came to be sealed in that world in the first place.
And the versions the Emperor and Estyr Six dealt with were pale shadows of the entities Suriel would be dealing with. When they're inside an Iteration, they're bound by its rules to some degree. Not so outside.