Harry saw the tension raising and knew it was time to begin. Blaise had gripped the officer on by the head then get grabbed by vines. Plus Tash probably was getting ticked off by the officers. So he moved closer to the group while remaining hidden. Then Harry focused on the rocks and began rearranging the molecules in each one. He could only do so much with them since they were so small. Once Harry finished his work he waited for a few seconds longer before he took his hands apart. Once his hands seperated the rocks each created a small explosion not big enough to do any harm but they each released smoke afterwards. This smoke could cover Tash's and Blaise's escape. Harry then took off himself to keep from caught he just hoped they used the smoke.