Since my readership threw a Sith-fit when I discussed the physics behind the Death Star superlaser a few months ago, I figured I was obligated to followup with McSweeney's take on everything that's wrong with the Death Star trash compactor.
To quote Joshua Tyree: "Ignoring the question of how
Princess Leia could possibly know where the trash compactor is, or that
the vent she blasts open leads to a good hiding place for the rescue
crew, why are there vents leading down there at all? Would not vents
leading into any garbage-disposal system allow the fetid smell of
rotting garbage, spores, molds, etc., to seep up into the rest of the
Death Star? Would not it have been more prudent for the designers of
the Death Star to opt for a closed system, like a septic tank?"
This is but one of nine points Tyree makes to illustrate what idiotic environmental engineers the Empire must have under its employ, if this sort of waste disposal system is considered top-notch. I say Tyree is misunderstanding the function of the Death Star trash compactor. So far as we know, the trash vents only lead up into thd detention block—exactly the sort of place that the Empire would want to be flooded with fetid smells and noxious spores. Thus, if prisoner cells are the only place the trash compactor vents toward, it also explains the idiotic tentacle-beast that lives beneath the water—it's an anti-escape device.
Without a plucky R2 droid hacking open the compactor and its magnetically selaed door, it's virtually escape-proof, and guarantees that horrible smells and tormented screams (either from the wall-crushers or the tentacle worm attacks) will reach up into the the Empire's dungeons. After all, when Luke insists that R2 "shut down all the trash compactors on the detention level," we have no way of knowing if their are comapctors on any other levels. I submit to you that there were not, as the compactors existed merely as cruel and unusal torment devices meant to soften up Imperial prisoners. If I was a Sith, that's what I would do.