Heh. If there was any chance fleeing would accomplish anything, I don't know what Sirous would do. But trying to flee would just make things more sportingly entertaining for the elves. They let us get nice and deep before they moved.
At this point, I think the only hope of anyone surviving is for us to kill or grievously wound Rhuobhe, possibly causing the treants and forest allies to stop fighting or to go out of control and causing massive morale issues amongst the elves. In other words, we are dead, dead characters. But we might as well try. Pile on the Awnshegh, people! Troops on the elven knights, heroes on Rhuobhe. And buff/heal/ward Braedonnal with everything you've got available.
And my condolences to the ETN and Hermedhie, who sent their regent/heir into the fray.