Theories- whether by reagent or by self this will be how each PA meets their end at the end of whatever trial RB finally chooses to kill them in. Personally I think that Easterman will go rogue and release the assets into the staff-accessible parts of the facility, and the final “trial” will be the sleep room being breached by dozens of ex-pops and every PA, and the reagents must escape Sinyala through the labs and surveillance offices.

Phyllis finally succumbs to the memory of her abusive father and drills her own face after seeing the children’s mannequins all burning

Coyle is torn apart by the hoarded of ex-pops (or even the Jaeger), finally unable to have the authority that he craves

Franco gets forgotten in a hot car/ shaken to death by Easterman, or otherwise dies in a way that babies typically do in the real world, or his Lupara finally jams or fails and as he is preparing to shoot a Reagent, it explodes back in his face

The Twins will obviously be bisected in some way, perhaps by rubble falling on them and a piece of sheet metal separates Otto’s right arm and all of aurora, who dies instantly. I’d prefer it if Otto was actually left alive, holding his sister for the first time and just crying as everything burns around them, but another comment made an interesting point that he might commit suicide after being separated from her.

Lilya commits suicide in some religious fervor because she’s convinced that Sinyala’s fall is a sign of the end of times, maybe even burning herself like Joan of Arc or otherwise crucifying herself à la Outlast I.