Alexis knew there was some kinda surprise attack coming. So instead of staying still, she darted back and up, it was on this preemptive measure she noticed her energy level. 

once she felt she'd moved back far enough she fired both barrels into the dust cloud, but then did something odd.

She, while the Buster Rifles where still firing, cut her engines and let Wing Zero fall a little bit while leaving the Buster Rifles to be pushed back and out of the arena by the thrust they generate. Once the Rifles where clear of the suit, she righted the suit and pulled out both Beam Sabers and took a defensive stance, ready for what ever Alex was gonna pull in retaliation.