It's good to let off a little steam after a stressful encounter or event in the game.
We also note that in this scene of the movie, it's quite clear that Luke has his lightsabre attached to his belt. So he obviously must have had it on him in the trash compactor. Yet he didn't use it.
This is clearly a major MacGuffin. A Chekhov's gun that will certainly have a use in saving the hero's life at some point. It's the single most fantastic and significant object in the entire movie.
And Luke never uses it except to deflect some remote bolts during the training session on the Millennium Falcon. Basically, there had to be a sequel, just so Luke could actually use the darn thing.
GM: So... You're outside the composter.
Leia: Phew. That was close.
Chewbacca: Yes, we can all breathe easy now.
Han: We should ditch the armour. We need to disguise ourselves as intruders.
Chewbacca: Or perhaps space tourists.
Luke: We're leaving the armour?
Han: We'll sell it later.
Han: Wait, I almost forgot.
[SFX]: Spang! Spang! Spang! Spang!
[SFX]: Spang! Spang! Spang! Spang! Spang!
Leia: Han! Will you stop shooting first! That is so annoying!!