In real life, if you get trapped in your basement your biggest motivation for escape would be that your going to die of dehydration in less then a week. If that same thing happens to a fictional character, expect every one involved to talk about how the person involved was "left down there to starve to death".
The only time you'll ever hear about people in fiction fearing dehydration is if they're trapped somewhere hot, like a desert.
This is presumably the situation because people associate dehydration with being hot and writers assume viewers are too dumb to realise a person will eventually dehydrate to death at any temperature if denied water indefinitely.
- In an episode of Star Gate SG-1 find a bunch of dead bodies in a sealed room on an alien planet, later in the episode when they ask a doctor what they died of she suggests hunger because they where locked in a room with no supplies
- In an episode of the English detective show New Tricks, they investigate the case of a girl who died after being locked in a cargo container, they say in the episode she took 40 days to die implying hunger not dehydration
- In an episode of Lewis where somebody kidnaps a priest and theologist visiting oxford, and for some complex bible related irony reason I don’t remember exactly decides to kill him by depriving him of supplies which results in him dying of hunger over the course of a month rather then dehydration over 4 days according to the shows ME character