Especially with that flashback in S2, you think Vaggie would be a bit traumatized over killing her former comrades, it's perfectly acceptable if that she doesn't have a breakdown during the battle and immedate aftermath, you could easily explain it away as adrenaline and being in a life or death scenario that leaves no mental room for that stuff. But just like Finn, Vaggie doesn't care later, she doesn't have any second thoughts of maybe if she tried hard enough she could convince at least some of the people she knew to give up and retreat back to Heaven to live to see another day even if none of them would fully turn sides.
There's a ton of parallels to be drawn with Vaggie and Finn, but especially so in how much both were such a missed opportunity to showcase how the normally faceless soldiers are actually people under those helmets, you don't need to dedicate a ton of screentime to this concept, maybe have a 30 second scene of Vaggie, obviously uncomfortable and thinking alone on a balcony, perhaps looking at Heaven, flashing between her being amicable with some of her former comrades and her killing them during the battle before another character interrupts her brooding would get the message across crystal clear without any dialogue.