Well, anyway, metagaming is definitely not an issue here. My players
actually yell at me to shut up if I start talking about the game outside
of a session so that I don't give anything away. If that leaves me on a
different page then them, then I have no idea how to do anything about
it. What are they concerned about, when it comes to you giving things away? But, you don't have to talk to your players about the game content, just their approach to it. You seem to think that they're being goofy and stupid. I believe that to be unlikely, and that it's more likely that they just see the game and the events in it differently from you. Talk to them, in general terms, about how they see their characters and their actions. Ask them if they believe they're being suicidal or whatever it is you're assuming. If they do, fine, you're right so just enjoy it. If not, you've got a starting point to figure out what the players are really up to, and to think about how to handle that. I know that the GM technically has complete control over
everything that happens, but the players in this session would probably
be more annoyed if I Deus Ex Machina'd them out of a certain death that
is their own making than if I just let them die. Here's the thing: there's nothing certain about death here. Sure, this situation should lead to more adventure, but there is no hard and fast rule that interacting with a devil will or should lead to certain death. It can lead to anything. I had to make one
radical change in the character of the devil they rescued to make it not
a guaranteed death sentence for the players to interact with it, but
that was okay, because I hadn't planned on them even talking to it, and
they didn't interact with it long enough to realize it had been changed.
I don't follow this. Unless you had explicitly told the characters about the devil's personality, then you didn't "change" anything. The devil's personality was always what it is now. And if you haven't explicitly told them that then the devil's personality can still be whatever you want it to be. Sure, every scene the devil's in is going to establish things and narrow down the plausible fiction, but nothing is written in stone until after it's stated, and most things aren't written in stone even then. Playing as if the stuff that's in your head is how things must be is what is putting you in a corner with how you deal with the players. If the devil now turns out to secretly be a good guy (or even just not
particularly evil) at this point, nothing could rationally explain what
it has already done. First of all, I doubt those are the only two options. Second of all, you're the GM and you have the entire fiction at your disposal. The only time nothing can work is if you say it can't work. If you don't want anything else to work, that's one thing, but that's your choice. More than one of my players is a published author,
and the rest are all very good fiction writers in their own right. They
will notice, and they will get mad, I really can't get away with much
retconning even if it is in the name of keeping them alive. If you haven't established a fact, then establishing some other fact isn't retconning. And what you describe is "buy-in" or lack of it. If they're really writers, then they'll know that nothing in a story is unassailably true, and that nothing works unless the audience is bought into it. On the other hand, if the audience is bought in, then almost anything can work. Star Trek is a prime example of this: it's full of atrocious holes, but its fans happily overlook them. If the players would see that death is the only entertaining option, then of course give them that. After you kill the characters, ask them honestly if they saw any other way that could have played out. Since they're writers, I bet you'll get a lot of other ideas you could have used, and it will be a shame didn't ask for those ideas in advance. Basically,
I'm just crossing my fingers and hoping they betray the devil before it
runs out of reasons not to betray them. At the very least I have a
complete control over making the signs that they should betray it really
obvious. No, you don't. You can't control how people see and interpret things. All you're doing is setting yourself up to be more baffled by these players when they don't understand what you're driving at, and to find them more and more stupid when you have to all but explain to them what's going on. But wait a second: they'd be mad if you changed an unestablished fact about the devil to save them, but they're fine with you basically telling them what to do to be saved? The only difference I see is that in the latter case, their original idea is completely nullified by your prodding them to do what you expected.