Bly had led the 327th through many battles, and was an accomplished Commander. He could not stand Secura due to her lack of experience and constant questioning of everything. Not just his orders or tactics, but also things like why he thought the mushrooms were so big on Felucia. He didn't have time for these things.
As the Battle was turning to their favor, Bly had finally had enough. All he had to do was nod to his officers, and the group opened fire on the Jedi After shooting her until their clips were emptied, reloading, and emptying them again, there was nothing left of Secura. After the sound of blasterfire ceased, Bly realized he'd missed a call and now had a voicemail from Chancellor Palpatine issuing Order 66. Crackerjack timing.