When Amelia throws the dirt to create a small smoke screen, Harley flips away from the direction that she had last seen Amelia. She just wasn't going to stand there and wait for an attack, while possibly unable to see... after all.

So Amelia will not find Harley to attack when she pushes through the dust cloud. Harley is giving herself a nice long distance, keeping away from Amelia, and waiting to use her yo-yo once the rogue is visible to aim a couple more shots.