Uhhh, if we're fighting that long, we're already screwed. It'd be useful for a front-lines commander, but any fight Ciaran gets in is going to be self-defense or a surgical strike. In the case of the former, if she can't outright kill her attackers, she should be attempting to flee before reinforcements zerg-rush her, and to delay for her own allies. With the latter,, we're usually pulling infiltration/spec-ops. Getting in an extended firefight is pretty much the worst case scenario.
Being able to last on extended missions is good, but getting stuck in a multi-day fight with neither our organization, nor our enemy's coming in to aid one side or the other? Not a very realistic situation.