As a GM, you need to remember every piece of equipment that the PCs have, and prepare your traps and obstacles so that they can be overcome, but not too easily. It's embarrassing to prepare a pit trap that should hold them long enough for the villain to escape, only to forget that they're carrying a ladder at the time.

Of course things will probably turn out the other way. Design a fatal trap with the obvious escape route using a piece of equipment they have handy, and you can virtually guarantee the players will either forget about it or decide not to use it.

Transcript

Han: Luke! Are you okay?
Luke: Yeah, lucky I had this underwater oxygen extraction apparatus.
Han: Use your laser sword! Cut a hole in the wall!
[SFX]: grind...
Luke: Are you nuts?! First, it's wet, it'll probably explode or something.
Luke: And if it doesn't I'll probably cut my own arm off!
Luke: Besides, I've got a better idea. Let's brace the walls.
Leia: Really?
[SFX]: clank...
Leia: Let me get this straight. We're going to brace the walls that are designed to crush junk... with junk.
Han: Yeah! Exactly! Great thinking, kid!
[SFX]: grind...
Leia: Use the fracking laser sword! Or give it to me!
[SFX]: clank...
Luke: We're getting squashed by solid metal walls. Do you prefer walls of molten steel?
[SFX]: grind...
{beat}
[SFX]: clank...
Leia: Let me help with that bracing!