Wendigos and Banshee wouldn't die of asphyxiation just because their lungs had been destroyed. Yet until their internal organs regenerated, they wouldn't be able to use their respective bloodline abilities that required their voice.
The heat from Solar Flare restored the hybrids' strength who instead had no problem with the scorching air.
The moment Kelia's tier one gravity spell, Feather Weight, allowed them to stand, Xenagrosh and Kigan unleashed respectively the tier five Chaos spells Flood Storm and Howling Hunger.
The former generated a tidal wave of Chaos that moved with the speed of a freight train, filling the corridor and turning the Banshees into nothingness.
The latter conjured a hail of black bullets that pierced through the Wendigos and riddled them with more holes than Swiss cheese until they turned into several piles of ashes.