It's just one specific use case for this technology that came to mind for the researcher? Mass shootings are a pretty big deal, even if the odds of it happening to anyone is fairly low. Risk mitigation and death prevention seems like a pretty healthy choice for applying this technology, as opposed to saying something like "This could let someone beam targeted ads that only the target can hear!"

"We made this thing, I wonder what we could potentially do with it that would benefit people as much as possible?"