I think it boils down to the fact that scenarios and encounters are designed to be the adventure. Extreme circumstances aside, to a player, running away feels like avoiding the adventure or worse- failing it.

As DMs, we know that hints are left for periphery details. A DM shouldn't be designing an encounter to be certain death, and they also have the power to have the players fail forward into new scenarios even if it becomes one. If an encounter must be deadly, then there should be no hints, you should be saying flat out this is not an encounter where the goal is victory through combat. Combat will mean death. Their characters can feel it in their bones.

DMs ought to avoid making encounters where the best course of action is to not engage with it on the players terms. And at worst, have more creative fail states than a TPK.