I'm honestly not sure how I'd solve this. I've been trying to imagine ways they can do this and "make it look good for the casual player", so to speak.
A very quick camera close-up and slow down before prompting you for confirmation?
Offering a short time window like a QTE rather than literally pausing the game?
Maybe a bullet time slow-mo thing?
The reaction mechanic is the only thing I really, really dislike because it removes the majority of control, strategy, and control involved with the way Reactions works.