Sirius felt the hairs on the back of his neck prickling, adrenaline rushed through his body as he approached the end of the tunnel, the last cell, which reminded him so terribly of Azkaban. He walked, thinking perhaps it had been his imagination when CRASH
The bars of the last cell had been kicked down from within, clattering on the tunnel floor. He coughed once from the rising dust when he saw something running straight towards him, "Stupefy!" he yelled, figuring it was better to stun first and ask questions later. Besides, he didn't mind hurting anything that made its home in a place like this. But the small, dark figure kept running, straight towards him –past him! "STUPEFY!" he screamed – he was sure he had hit it this time, but it kept running. Swearing, he ran after it, pulling it back before it escaped the dark tunnels.
The man had me! I was so close to escape, so close, but he pulled me back, sending me flying back towards the ground! I let out a roar of agony and anger, he had stopped me! I NEEDED TO GET OUT! He waved his wand at me yet again, saying incantations, trying to stop me, trying to make me sleep, but it didn't work of course, it never works…
By now, Sirius had realized that the creature was in fact, human. Or at least human in appearance, but he had his doubts considering that, for such a small creature it was putting up quite a fight. The wand was promptly kicked out of his hand, not that it seemed to be doing him any good. He felt a fist collide with his jaw, which really pissed him off. With all his might, he threw the person off him, but it twisted in the air, landing neatly on its feet in a crouched position! It tried to run past him once again, but Sirius had had enough. He stuck out his fist, and when the figure went to dodge under it, he extended his leg, tripping it, causing it to fall most ungracefully. Before the figure could leap up again, Sirius had jumped on it, pinning it to the ground. Small as it was, Sirius's weight was too much for it to hope to struggle against. Sirius smiled in relief. Reaching for his wand, and still holding his captive down, he sent a message for reinforcements.