EMH: His jaw's been fused and his vocal cords removed. I might be able to undo some of the cosmetic damage, but only Q can restore his voice.
Q2 seals Neelix's mouth shut and removes his vocal chords, no visual intervention other than Q2 saying 'you talk to much'
Q: I think that's long enough. (snaps fingers)
Q2: What was that for!
Q: What's wrong? You didn't enjoy life as an Oprelian amoeba?
Q2: No, I was shapeless and slimy. The only thing to eat was paramecia.
Q: Sounds unpleasant. I'm sure you'll do whatever you can to avoid returning to that petrie dish.
Q2: What are you talking about?
Q: The Continuum and I have come to an agreement about your future. Either you become an upstanding citizen of the cosmos, or you'll be sentenced to eternity as a amoeba. How's that for consequences.
Q2: You'd turn your own son into a microscopic lifeform?
The Q can transform one lifeform into another, can any other technology in Trek do that?
Though another interesting quote from the Q2 episode is:
Q: We've temporarily relieved you of your powers, to ensure that you're on your best behaviour with the Captain.
Q2: You're leaving me here?
but then we hear
Q2: Do you think it's easy to live up to my potential? I was supposed to be the saviour of the Q Continuum. Tell me, how do you save a race that's already omnipotent?
Bad writing I guess
Anwyay, moving on
CHAKOTAY: One of your responsibilities as a Q is to maintain order in the universe, right?
Q2: So I've been told.
PARIS: Steady, ease up a little on the thrusters.
Q2: In case you forgot, I'm mortal now. I'd appreciate it if you didn't fly us into a rock
So relieving them of their 'powers' also makes them fully mortal- thiswould seem to answer my earlier question- they are incapable of dying as Q, while they have their 'powers'
As for technology argument:
Q2: Ordinarily a Q wouldn't demean himself by operating primitive machinery, but these aren't ordinary circumstances.
Note he says 'primitive machinery', hmmm