Draco's own patronus had disappeared forcing him to unable to fight with the dementor in front of him. The camera had had clutched in his hands fell to the forest floor. He felt cold and weak unable to move where he was. Any happy memory he had left was replaced with his own fear and despair.

The wolf had charged at the dementor causing it to release Draco and sending it off. Draco then collapsed where he was.