Cassius was not denying her -- however, a thought occurred to him. [color=0072bc]"At the very least we can get them closer to the bunker, staying far out is the most suicidal thing we could do! Move closer to the bunker, splitting up, or not!"[/color] 

He would admit she isn't wrong, but one thing also occurred to him... These were creatures, not organized people, who they follow, or burrow around to, would not matter due to the fact of them not being able to predict where they'd go.

[color=0072bc]"If they can burrow, it would be wiser to collectively move to the bunker, if we can collectively get in, then the odds would be even better, worse case is we are stuck killing one off before we enter. Fight only what you need to, and leave the rest!"[/color] These were the most rational orders he could think of given the situation. 

They could pass under sand, loop around, there was no real way to determine where they'd go until action was taken, and the reality is, split up, or not, their odds are better if they move to the bunker at any rate, if closer to the walls, it means the creatures have less chances to come from different angles. At least, that is how he rationalized it. [color=0072bc]"If we are closer to the walls, they have less directions to swarm us from, making them easier to hit!"[/color] He was trying to clarify his logic to them.