There are improvised weapons everywhere. Make sure you have a handy random table to roll up something that a desperate character might find in the area to pick up and use as a weapon. If you need some ideas, use this one:

Roll 1d20:

1. Stick
2. Rock
3. Horseshoe
4. Chair
5. Beer mug
6. Candlestick
7. Kitchen knife
8. Bucket
9. Rake
10. Scythe
11. Pitchfork
12. Anvil
13. Book
14. Shovel
15. Skull
16. Electronic tablet device
17. Bunsen burner (lit)
18. Vegetable peeler
19. One of those miniature Eiffel Towers that everyone buys in Paris
20. Musical instrument, roll 1d8:
    1. Flute
    2. Lute
    3. Guitar
    4. Viola
    5. Trombone
    6. Piano (upright)
    7. Piano (grand)
    8. Theremin

Transcript

[SFX]: crunch crunch
Rancor: Hmm. Tastes like... a rubber chicken.
Luke: Um. So... you're trapped down here too, huh? How about we team up?
Rancor: I shall eat you with some jawa beans and a nice Chandrilan Blue '439.
Lando: Wow. That thing has taste.
Luke: Okay... I need something to defend myself.
Leia: Where's your laser sword?
Luke: Gosh, I must have left it in my... right hand.
Han: You came here with no weapon??
Luke: Oh yes, because laser swords have always worked so well for me.
Luke: I search the room.
GM: You find <roll>... a large <roll>... bone.
Luke: All right, that'll have to do.
Rancor: Oh, what now then? Enthrall me with your acumen.
{beat}
Luke: Um... I've got a bone to pick with you?
{Leia reacts to the horrible pun}