Even Evil Has Standards:
One of the easiest ways to highlight just how bad something or someone evil is: have an otherwise-remorseless villain reject it.
Protectors Of The Plot Continuum usually do their best to save Mary Sues' children, if they're not Sues themselves. They also seem to have a restriction on killing Sues in any way which involves rape - Agents Laburnum and Foxglove are responsible for two of these methods actually being banned more specifically (the Redneck Trees and Drip Tiberius Rat), and got in big trouble for them, though since the Marty Stus executed thus had committed graphic rape themselves they got in slightly less trouble than they otherwise would. In Laburnum's words:
"I always thought that rape was the one unforgivable crime, and there was no way of justifying it at all. However, I'm prepared to make an exception in your case."
"So you're letting us go?"
"Nope. I was talking about your punishment, not your crime."
And then the Sunflower Official informs Laburnum and Foxglove that using the Redneck Trees as a form of execution comes under the heading of "Going Too Far Even For The PPC". The use of historical atrocities such as the Holocaust as an assassination method is similarly forbidden; it's unknown if anyone has actually done it, however. Torture is also not allowed, and tends to result in arrest; torturing a Sue generally earns a reprimand, while torturing an agent can get one thrown out of the organisation entirely.
Also, HQ bicycle Agent Lux glomps and gropes anyone who stands still long enough, but the only time she's been seen genuinely angry onscreen was when she walked into a scene where the villain was about to rape his six-year-old daughter. ("Mulla" was adopted and renamed Molly. Possibly bringing her home wasn't the best idea.)
""Fine, fine," Lux muttered. "Snot like she's a real kid, you know. . ." The words died in her mouth as she stepped through the portal and took in the scene at the other end. Mulla the ferretmaid lay curled up on Sawney's bedroll, shaking as the Juskarath chieftain loomed over her. She looked like she was about to start crying. "Nevermind ..."
One of Lux's recent paramours was seventeen, but they were - technically - in the UK, where that's over the age of consent (16), so it was okay. Or it would have been had they been of normally-compatible species, so as it was, age was the least of the onlooker's worries.
Improvised Weapon:
A creative fighting tactic used by unarmed people in any situation: Make what's around you a weapon. Even outside the dangerous environments, there's a lot of stuff to try. Anything can be used as a club if it's sturdy enough, and most stuff will develop a sharp edge if properly coaxed. For comedy value, go as wacky as you like.
Protectors Of The Plot Continuum does this a lot. Beating people with books is part of the exorcists' usual modus operandi, as they need to knock the canon back into the characters in question. One particularly impressive example involved Agent Drake beating a victim to death with a dildo (which she had just finished using).
O Ring Orifice:
Protectors Of The Plot Continuum occasionally finds and mocks instances of this, as in one story where a guy successfully fits his penis inside another guy's urethra. And you wondered why Mary Sues must die ... Also, the incident in which a Plot Hole (which, in the PPC universe, are literal wormholes in which the characters the Sues have replaced are hidden for the duration of the fic) was found inside a Sue's uterus, resulting in a particularly disgusting scene in which she gave birth to the full-sized teenage girl she'd been imitating. This shows up so often it's listed on their Charges page on the Wiki as "Not There".
Rape As Comedy:
* Using rape in a disrespectful manner is officially disapproved of by the ProtectorsOfThePlotContinuum, but in higher-rated missions it has been used twice (by the same writer) as a CrossesTheLineTwice-type gag. Once, two "pointless rapist bit-characters" were executed by means of the Redneck Trees of Something Positive, and another time a Villain Stu who did unspeakably Squicky things to the cute little animals of OverTheHedge was given to Drip Rat of the webcomic Jack in retaliation. The agents involved were punished and forced into therapy, but it was played for slightly-uneasy laughs onscreen. The same agents recently sporked a fic which featured the Narmful line "There's nothing more painful than being anally raped!!" It shows exactly how AxCrazy these two are that their first response, after they'd stopped laughing, was "Yes there is" According to Agent Laburnum, a basic rule of fic sporking is "any fic with the word 'rape' in its title is probably going to be brain-meltingly bad".