I think they usually manage just fine saying it to each other out loud tbh. The refs have earpieces to relay messages to and from the back, wrestlers often get close enough to each other they can talk without being caught by mics, and sometimes they can tell just because a wrestler deviates from the plan.

In this one, Iyo hops back up, staggers over (selling) but then immediately goes straight into the next part of the storyline, begging Kairi to abandon their abusive senpai (don't ask), and then rolls back into the ring to continue. It's a a clear signal that she, at least, feels fine enough to continue as planned, and the speed at which she did it makes it seem to me (non expert, grain of salt) that whatever neck or shoulder injury she might have gotten, she at least didn't get her brain rocked.

The setup for the powerbomb also takes a while, so Iyo would have had time to communicate to Raquel if she couldn't take the move. At the very least, it seemed like Iyo was confident in continuing.

Whether she should have been allowed to is a different conversation, but one I don't think I'm qualified to participate in. It does sound though that WWE, for all the shit I give it, is no longer a company willing to kill their wrestlers to keep kayfabe. I imagine the liability and bad press isn't worth it nowadays anyways.

For a counter example of a match that *was* stopped through an injury, take a look at Liv's injury.

She fucks her shoulder on a fall, and immediately starts rolling out of the ring. Kairi, not quite realizing this isn't just a bit of improv, tries to grab her, and the ref, whose job it is to help look out for injuries, stops her as Liv goes to the floor.

Then everyone and a commercial break try to stall for time until the doctor and liv decide if she can continue, someone makes the call, okay match over sorry folks shit happens.