Based on the video shared by Reuters, I'm not seeing anything that would focus the attack to the pager's carrier. Anyone standing next to the target would also risk severe injury or death.

ETA: I should perhaps clarify: focus the attack exclusively on the pager's carrier. It does appear to be modestly shaped in some way (in that we're not seeing the pagers go up in a 2-meter-radius fireball), but it's also not contained exclusively to the carrier, has no verification that the carrier is holding the device, etc. Whether one considers that "focused" is left as an exercise for the reader. Certainly more focused than a rocket; a bit less focused than poison.