[quote=@Little Bird]
Logistically speaking

Zac would likely be more concerned about getting himself and others to the ship. Anyone going with him would only fight to the extent that it gets them on board. 

Anyome getting off world by other means will be left fighting. 
[/quote]

This is pretty much my thought process. He's just fighting to give the others a chance to get to the ship. Soon as everyone or nearly everyone's accounted for, he's gonna dip and get everyone in the ship out of there