Jack Douglas and the water pit he claims he knew nothing about

On the audio commentary Jack Douglas claims he did not know there was a massive 8 feet deep water pit immediately outside his character's caravan and that he fell in...

Why do some people feel the need to make up stories especially for an audio commentary where what is taking place onscreen clearly contradicts what is being claimed?

But then again this is the guy that seemed to think that twitching violently again and again is somehow hilarious.