Exactly. I remember early days of smartphones before a lot of the safety precautions we have today were implemented, where we saw tons of videos of batteries spontaneously combusting. They expand, there’s a pop, and then a small burst of flame that will ignite anything it touches, like your pants, tables they’re sitting on while charging, etc. You can get pretty badly burned if this happens while it’s in your pocket.
It’s just that the videos that have come out of these pagers shows an actual explosion, as if they had been packed with C4. Enough to instantly kill some people with them on their person and harm adjacent passerbys.