Okay so I am running a Starfinder homebrew campaign and the party should be level 3 or 4 by the time they get into the area I am writing now. I have them exploring an derelict space-hulk I have a few decks that are malfunctioning holo-decks and on this one floor is where I need some outside advice I want to put a locked room with a save or get sucked into space trap, essentially a save or die trap and I'm wondering if that might be too early for that and/or what you would do for detection that the door would be vacuum on the other side?
Thanks for any help
Save or die traps are literally no fun. Just like save or die spells.
One failed save shouldn't result in death. Of course, your players should all have space suits so it's not immediate death. Just the risk of possibly dying from drifting out into the nothingness of space will eventually result in death from a lack of oxygen.
Also, for what it's worth hard vacuum will usually not result in any person getting pulled out an opening into space. It doesn't generate enough force to move a person significantly, assuming artificial gravity is functioning.
Yeah, at the very least have it require multiple failed checks and saves before death.
Being ejected into space wouldn't even be that lethal unless they left him, presumably they have a ship (otherwise how'd they get to this space derelict?) so all they gotta do is go scoop him into the cargo hold
They're probably all wearing armor, meaning they can activate environmental protection with a standard action. Even if they float off into space, they'll have a few days before dying of either dehydration or running out of oxygen. Also, you can float through space just by throwing stuff, shooting a projectile weapon, using a fire extinguisher, what-have-you. Your planned save-or-die situation would mostly just be save-or-mild-inconvenience.
But as others have said, you shouldn't do a save-or-die, anyway. Save-or-die spells usually allow two or three throws to avert and I think even that is really annoying.
But if you wanted to do it, here's how I would handle that:
1. Engineering checks to assess the structure of the door. Maybe they can notice some air escaping or the door bulging outward. Maybe a good Perception check, too, especially if they have Blindsense or something like that. Maybe an Intelligence check to remember that, hey, when they flew past that earlier, there was nothing there.
2. If that fails and they open the door, Reflex save to activate environmental protection in time and to hold onto something. If you want to be particularly cruel, make them choose whether they'd rather hold onto something or be able to breathe. If they fail, they manage neither.
3. If they don't activate environmental protection, Fortitude save to not lose consciousness. If they succeed, they take damage, but can activate their environmental protection in the next round. If they fail, they're unconscious and start suffocating (CRB, page 404) until someone rescues them (activating someone else's protection is a full action).
This would not be instant death, but if someone fails both saves, they are in pretty bad shape and dead in a few rounds if nobody saves them.
As to the skill check in step 1, you probably shouldn't explicitly prompt your players to make those checks unless they specifically ask. I would make an exception for something like Engineer's Eye, but apart from that, let them ask you.
Unless, of course, there's some players new to RPGs in the group. But in that case, you should entirely abstain from save-or-die in general until Raise Dead becomes reasonable.