It could be said that whether one was in the Bronze Resonance Realm, the Gold Resonance Realm, or the Cloud Resonance Realms, the true state of one's Mana was a gaseous form.
The first three Realms were a crutch, and that crutch was only slowly being released at the Cloud Resonance Realm. But even then, it was still just the beginning.
By this logic, though, Theron realized that even when you managed to convert your Cloud into a Dome of Heaven, you would still be relying on this crutch. However… you would be much closer to shedding the need for this crutch entirely at the same time.
Why was it that Theron could put his hand in the cloud without being crushed?
Well, there was Mana much more powerful than himself all around in the world around him. Manas of Resonance so great and powerful that he couldn't hope to control them even within a decade, even on this planet occupied by such a weak Sect.