Primordial Demon might have frozen him in time, severing his past, present, and future, but Rowan's consciousness and Will had been tempered to the extent that he could still have awareness, even in this state.
However, his awareness was diminished due to the fact that he was used to seeing all facets of Reality at the same time, his senses piercing through all dimensions and laws, but now his awareness had been reduced to a pinhole.
In this state, Rowan made an awful realization. He had evolved into a being that could never truly be killed; his present state had left the Primordials behind, at least the ones within this Reality.
Even if all parts of him were destroyed, his Will and awareness would remain, severely diminished, but still remain. If he made no plans to quickly resurrect himself, then it was possible for him to stay in this state for all eternity. Silent. Watching. Unable to move, speak, or change the world around him in a meaningful manner.