Plan for a one off session on Halloween

[Railak]

So, I'm planning a sort of one off Halloween session with my group. Using the Fallout PNP 2.0 rules, cause I have them and understand them pretty well. The game mechanics aren't really why I'm posting though.

So I'm doing an Among Us/the Thing/Alien sort of idea. Basically the group was mining on another planet, while they were on planet one of the character's pet dog was attacked by a parasitic organism that's fairly intelligent. It took over the dog and went back with the crew onto the ship, where they departed. Well after a couple days of flying through space, the party will hear gunfire and come across the security officer gravely wounded, doesn't survive. She does exclaim that the dog wasn't the dog and it was some sort of creature that attacked her.
The creature wounded by the bullets that hit it ran off through the vents and hides out in a place they can't locate it. During the night it creeps through the vents and infects one of the other crew members. The person who is being "infected" doesn't know they are right away. When the person is alone with another person for a while the creature shows itself and attacks the other person trying to multiply by injecting some of itself into the other person.

At this point both players will know they are infected and are given the goal of either infecting more of the crew or killing them for food.

So to save on time I already created the characters, each one has something about them.
Scott a male pilot, married to Janet, he has a handgun, that he keeps on his person at all times.
Janet a female engineer, who is pregnant with Jane's baby, will do whatever it takes for no one else to find out.
James a male mechanic, convict out on work release, he is very charming with the ladies, he has some prison tattoos and some medical screws in his shoulder, so he hates going through medical scans.
Sarah a female doctor, mother of Mikey, and an old friend of Scott's, and has a crush on the captain she's trying to get over by sleeping with James
Mikey a male navigator, he's young, but very intelligent and skilled. He has a habit of sneaking around and eavesdropping on people. He steals things from Janet for fun.
Xavier a male captain of the ship, he is turning 50 soon, and the company is forcing him to retire after they return with the payload, because he also learned he has cancer. He doesn't want the crew to find out about either thing.

So the hard part is going to be keeping the group from metagaming, I thought about separating them, based off who they're with.. but that might get weird.. I plan on using phone and text for a lot of things either way.

Course this whole thing may just sound good in my head and be a complete nightmare to actually run. But I really want to try it, so any advice on making it work will be helpful.

[The Glyphstone]

The only way to keep them from meta-gaming is buy-in. Get them invested and willing, and it'll work. Otherwise, it won't.