Amazing chapter, too bad for the hiatus notice, though :feelsbadman
Anyway, time has finally moved forward in the series, as in we're past the time announced in chapter 410 (40 minutes into special martial law)!
I believe Halk's power would make their souls coexist in Tserri's body, and the time limit refers to him losing control to the original soul once the body wakes from sleep.
She probably can see him, perhaps because of a rule governing his hatsu that he, himself, isn't aware of, or because of a interaction between nen fundamentals, regarding her scar and the effects of the guardian spirit beast's hatsu.
That would be interesting. What if they both are, and their actual job is to keep him alive, so Beyond wins in the end?
Bonus points if his objective is to turn himself into the new king of kakin by the end of the ritual, and to acquire every single one of the guardian spirit beasts by means of...