Short version: I don't know enough details about the tower scenario so I'll discuss one that happened when I was DM and why it turned into a near TPK.
Long version:
Long, long ago, I would bend over backwards to save all the PCs. That PC that chased after a chest of gold about to fall off the edge of the crashing airship? Give 'em saving throws and options until they make it out alive. That TPK when the group decided everyone in the group should play some variation of wizard? The bandits just sold them into slavery. Been there, done that, got the lousy t-shirt.
Eventually I realized that it never really sat right with me or the group. So we discussed it and I adjusted. I wouldn't go out of my way to kill PCs, but death is never off the table either. Have your PC try to steal something when it's been explicitly stated that the shop owner is watching you like a hawk? The guard is called. Try to fight the guard when they arrive (and you're a first level PC) well, you haven't been playing that PC too long so write up a new one.
Then came the orc encampment. The group had been hired to find out information, try to find more information on the orcish raiders. They found a large encampment with more orcs than they could reasonably take on themselves. They knew they could go back and ask for reinforcements, or perhaps they could have started ambushing patrols to whittle down the numbers. It looked like a direct assault was not a good idea.
One of the PCs decided to sneak into the camp to see what they could steal. They find a big chest mostly full of copper and junk, but quite a bit of treasure. Too heavy to carry off, they start dragging the chest away, alerting the guards. Instead of running when the alarm went off the PC continued to attempt to drag the chest. Hearing the alarms, the other PCs also ran into the camp to save their friend.
In that scenario? The only one who survived was the wizard who ran away. What exactly was supposed to happen here other than the orcs attack the intruders? They didn't know the exact number of orcs, but the PCs were fairly low level and outnumbered. I don't control the actions of the PCs and the orcs were not the forgiving kind.
So now when we start a new campaign we discuss the options in the group's session 0. I tend to run a fairly low lethality game but death, even TPK, is never off the table. Come across a large orcish encampment or seek out a tower simply because you heard it's dangerous? Charge into that encampment without a plan or try to sneak past a demonic guard? You face the logical consequences of what I, as DM have already place there.
There are very dangerous places in my campaign world. Places that will be a threat to even high level PCs. Decide to go into those places without further investigation, without prep? Just try to sneak in past the guard that's way above your pay grade for no other reason than curiosity or greed? You get what you get. Maybe the rumors were just rumors and the demon is an illusion or maybe it's a meat grinder. What it won't be is automatically adjusted to be an appropriate threat level for your group.
The game world doesn't revolve around or morph to suit the needs of the PCs. Because it's a game I'll dangle threads about things they can handle. But I won't give them info I don't think their PCs would not have. If they go off on a tangent and don't pause to assess the danger but go in blindly or ignore the fact that the doorman is a demon? Let the chips fall where they may.
Long version:
Long, long ago, I would bend over backwards to save all the PCs. That PC that chased after a chest of gold about to fall off the edge of the crashing airship? Give 'em saving throws and options until they make it out alive. That TPK when the group decided everyone in the group should play some variation of wizard? The bandits just sold them into slavery. Been there, done that, got the lousy t-shirt.
Eventually I realized that it never really sat right with me or the group. So we discussed it and I adjusted. I wouldn't go out of my way to kill PCs, but death is never off the table either. Have your PC try to steal something when it's been explicitly stated that the shop owner is watching you like a hawk? The guard is called. Try to fight the guard when they arrive (and you're a first level PC) well, you haven't been playing that PC too long so write up a new one.
Then came the orc encampment. The group had been hired to find out information, try to find more information on the orcish raiders. They found a large encampment with more orcs than they could reasonably take on themselves. They knew they could go back and ask for reinforcements, or perhaps they could have started ambushing patrols to whittle down the numbers. It looked like a direct assault was not a good idea.
One of the PCs decided to sneak into the camp to see what they could steal. They find a big chest mostly full of copper and junk, but quite a bit of treasure. Too heavy to carry off, they start dragging the chest away, alerting the guards. Instead of running when the alarm went off the PC continued to attempt to drag the chest. Hearing the alarms, the other PCs also ran into the camp to save their friend.
In that scenario? The only one who survived was the wizard who ran away. What exactly was supposed to happen here other than the orcs attack the intruders? They didn't know the exact number of orcs, but the PCs were fairly low level and outnumbered. I don't control the actions of the PCs and the orcs were not the forgiving kind.
So now when we start a new campaign we discuss the options in the group's session 0. I tend to run a fairly low lethality game but death, even TPK, is never off the table. Come across a large orcish encampment or seek out a tower simply because you heard it's dangerous? Charge into that encampment without a plan or try to sneak past a demonic guard? You face the logical consequences of what I, as DM have already place there.
There are very dangerous places in my campaign world. Places that will be a threat to even high level PCs. Decide to go into those places without further investigation, without prep? Just try to sneak in past the guard that's way above your pay grade for no other reason than curiosity or greed? You get what you get. Maybe the rumors were just rumors and the demon is an illusion or maybe it's a meat grinder. What it won't be is automatically adjusted to be an appropriate threat level for your group.
The game world doesn't revolve around or morph to suit the needs of the PCs. Because it's a game I'll dangle threads about things they can handle. But I won't give them info I don't think their PCs would not have. If they go off on a tangent and don't pause to assess the danger but go in blindly or ignore the fact that the doorman is a demon? Let the chips fall where they may.