Because of Chet.
They played so much better before chet called a timeout. After that, they stopped thinking. NRG should have just fought for A main control, but they never did that. All they did was send a prowler and hold.
By fighting A main, C9 might have been forced to go to B, which NRG were really good at retaking.
I wish that they didn't do the same thing every single round.