From StrategyWiki, the free strategy guide and walkthrough wiki

Stage	Chapter 15: Lab Rats
Winning Condition	All Blue units escape but don’t let both the blue recon nor infantry to die
Player Commander		Opponent Commander
Name	Brenner / O’Brain / Brown	Name	Waylon
Faction	12th Battalion / 12th Independent Legion	Faction	The New Rubielle Army

Brenner dislikes the orders done by Greyfield and wants Tasha and Gage to survive. So Brenners Wolves and Lazurians escaped but Brenner sacrificed himself to save everyone.