I think we're still doing quite well on resources (spells, hitpoints)? If so, I'd vote for continuing to explore this area near the elevator. But I'm OK with it if everyone votes to head up now. We may be doing well on those resources, but how are we doing on carrying capacity? If we're overloaded,...
Rhod will stand watch while the rest search the room. Once the chest is opened, if there are other things than gold pieces in their, then he might use Detect Magic. But only if there's something we suspect is magical.
Actually, the first thing Rhod will do is use his sword to Detect Metal. That should tell us if there is treasure in the chest, at least of the metallic type. And it might also indicate any metal bits of traps that might exist, too.