Based on one brief moment of dialog from this week's episode, if someone truly is going to die as the previews suggest, I think it's going to be
Or maybe there's HR blowback on Fusco and he gets taken down by the authorities, so he falls but doesn't get killed.
OK, why would you spoiler code that? It's not a real spoiler. You don't know anything that the rest of the fans don't know. You're just spit-balling. So why bother spoiler coding your guess?
That said, I'd imagine they'd kill off Reese before killing off Bear. They have Shaw waiting in the wings to replace Reese, but who could replace Bear? And it's not like the dog can appreciate a well-crafted death scene, while human actors seem to love a dramatic death.
Granted that Reese is more or less the main character, but then killing off Hartnell's Doctor was similarly shocking, but now we're used to the idea of the main character changing out regularly. It could be POI will end up going this route in the future, with Finch regularly replacing his field operatives.