Sometimes one character will know something that other characters don't. They can choose to share it with their fellows, or keep it a secret - assuming of course that they're in a position to share it with their fellows. If they can't communicate with other PCs, then there should not be an option to share the information, assuming they are faithful to the game situation.
However, some gaming groups may ignore this restriction, casually sharing information among players that should be privileged knowledge, and not have any significant impact on their enjoyment of the game.
In pragmatic terms, there's no right or wrong way to do it, as long as everyone is on board and having fun.
Commentary by memnarch (who has not seen the movie)
I was surprised by Pete being good at player/character separation as well, but then, I always took these comics to mean Pete didn't do that. I'd never really thought about it after making that mental decision, but at the same time, being good at it and actually playing separate knowledge are two different things. So on the whole of it, I should have remembered that Pete can be very good at roleplaying knowledge separation when he's got the motivation for it.
So what could the cone bit do? It looks like it's half again as large as a grenade, so it's probably not your usual handheld device. Assuming it's a smaller component in something else, I could see it being a power source for a powerful ship or other kind of vehicle, or the start of a superweapon. Or perhaps its going to be a one-of-a-kind hologram projector that doesn't have the grainy blue limitations that all of the other projectors seem to have. That'd be very useful for fooling others with if it's exceptionally realistic.
Also interesting to note that Pete hasn't been told that Jim's character tried to turn traitor. Or maybe he does know and doesn't want them to know he knows, as he didn't come up with a different word that would implicate that knowledge. I think we're definitely rolling towards a party versus party game. I wonder if we'll be staying that way for the whole movie trilogy or if team antagonist will get to play some smaller role characters on team protagonist.
Commentary by Keybounce (who has not seen the movie)
I wish I could tell you more about what's going on here, but that's confidential information.
"Ahem. I have security clearance".
What is your security clearance?
I'm sorry, that's not sufficient clearance.
(Maybe I should have claimed ultra-violet?)
[SFX]: scrub scrub scrub
Rey: I clean the double-ended cone and examine it in the daylight to see if it’s what I’m hoping it is.
GM: It looks very much like the schematics. Correct length, shape, details.
Kylo Ren: What is it?
Rey: That’s privileged protagonist character knowledge.
Poe: What is it?
Rey: That’s privileged... character knowledge.
Finn: Are you separating player/character knowledge? That’s—
[SFX]: < boop bedoot >
Finn: ... something you’re actually good at.
Rey: Thanks for noticing.