Opal could try opening up a very small portal to slowly equalize the pressure or communicate with a cohort, but of course her cell is closely monitored, and the time it would take for her to decompress is multiples of hours, and they’re not going to let on how many atmospheres she’s experiencing at the moment.
Pressurizing a cell effectively negates several problem powers. Teleportation and portals, as well as phasing. It probably introduces a bunch of other complications, but in a world without alien or magic “Power-B-Gone” tech, or some peculiar substance like vibranium that phasers can’t penetrate (not Star Trek phasers… you know what I mean) you have to start getting creative. Of course there’s the induced coma, but as far as I’m aware there are significant risks to keeping someone in a state like that for an extended period of time. To the best of my knowledge, people can live in a high pressure environment indefinitely, it’s the decompression that’s the dangerous bit. Beyond that I’m not sure how else to incarcerate someone to whom physical barriers are meaningless. Maybe a poison that requires regular antidotes? A shock collar that activates as soon as their powers do is super risky because it would have to incapacitate them before their powers carried them beyond the effectiveness of the collar, and that assumes you can create tech that can determine when a power has been activated and doesn’t knock them on their ass every time they sneeze.
People don’t get to chose their names, and most parents don’t name their children by factoring in the possibility that they will one day become a crime lord, supervillain, or vampire lord, and will therefore need a threatening sounding name. That said there’s probably not a lot of mob bosses naming their first sons Mortimer.
I like the name Kevin for Vehemence because as names go, it’s humorously non-threatening. Apologies to any readers named Kevin who are looking to dominate the MMA world or become despotic dictators or anything. The most intimidating Kevin I can think of right off the bat is Kevin Spacey just because he can play some pretty intense roles, but really if you say Kevin to me the first place I go is Kevin Smith. After that there’s Bacon, Costner, Hart… uh, Nealon, Klein, Pollak… beyond that I’d have to start googling. None of whom really strike fear into anyone’s heart. Most major supervillains tend to have cooler or threatening sounding names; Victor (von Doom) Sebastian (Shaw)… also Sebastian the Crab so maybe that one’s a wash, Lex (short for Alexander Luthor). I try to not play that game when I can, or play against the trope like in this case. Deus is the obvious example of me breaking my own rule there.
This only applies to humans who become supervillains and not guys like Brainiac, Darkseid, Ultron, what have you. When it comes down to it, Brainiac and Ultron were given names by their creators probably with the intention of making them sound cool. Darkseid, well, we pretty much have to take his word that that’s his real name. I mean he might have been born Kevin McGeoghegan, but anyone who questions his current moniker get the Omega Beam express.