While I love the idea of Elita becoming unethical in the war against the cons, I have an alternative: Elita struggling to not commit warcrimes and genuinely trying to be merciful except she barely knows what 'mercy' is and it's played for comedy as well as seriousness.
*In a Decepticon ship that's going down.*
Starscream *Is unconscious*
Optimus: What about Starscream?
Elita: *To Soundwave* You'd better tell us, or else I'll slice off your fingers a centimetre at a time!
Arcee: *Disturbed if a part of her is impressed* Primus, Elita!
Elita: What? It's better than the first threat I thought to give him!
Elita: (In her most intimidating 'Superior officer' voice) Did you just spray me, Scout?
Bumblebee: (Sprays her again with a scolding beep)
Elita: Hey! Okay, okay! I'll be good! Yeesh!
Elita: (To a group of Decepticons over a megaphone) Surrender now, and we won't kill you! We'll probably- hang on. (Turning to Optimus) Is blasting their arms and legs off even if they do surrender ethical? I genuinely can't remember.
Elita: (Throwing a food tray at some prisoners) EAT OR STARVE, CON SCUM!!
Ratchet: (Forced to be the restraining element in the group while Optimus is away) Elita!
Elita: (Facepalming) Right. Right. (Trying to be polite) Uh, please eat, but there's no pressure!
*The Prisoners finish their bowls in seconds in utter terror of 'Polite Elita'*.
Elita: Optimus, is it a war crime to trap an enemy in a torture dimension where they can't die?
Optimus: (Very, VERY tired) Yes! Of course it is!
Elita: ...I'll go fix it.
Optimus: What did we learn?
Optimus: Excellent! Want an energon cookie?