Peter felt his heartbeat slow gradually from major panic mode to only moderate panic. Perhaps this Dumbledore - yes, he was a little younger, maybe. It was hard to tell with Dumbledore, but it made sense - if the man knew him and knew him well enough to know what he had done, Peter had no doubt there wouldn't be enough left of him to fill the fish bucket.
"Sorry," he said eventually when he had his breath under control. He scrambled up and brushed the sand off his now-dry clothes, keeping what he hoped was a safe distance from the man in any case. He could feel his wand burning in his jacket pocket.
Don't even think about it Pete. The man is the best dueller that ever lived. Even the Mas - even You-Know-Who is afraid of him. Keep it together.
"I... er...." he stammered, trying to come up with an excuse for his behaviour. "I was..."