The wave of fire did cover up Gohan's attacks and hiding the energy with energy made it difficult to tell the two apart.

Stardust tried to simply power through it, still trying to go after Alexander. The blasts made her have to dig her feet in the ground with each step to avoid being knocked back.

Everything was lining up. Her back was to Superboy now, so if he could get the mining equipment above ground in the next few moments, they'd finally be poised to take her down.