I think your dream was quite close to what you might do in reality then, instead of answering him you ran away to the door and laughed, like your brain in running through the scenario to see what you would do if it really happened.

Although if you did do that I'm not sure what the guy would think if you did run away and laugh, he would probably be embarrassed himself if he got the courage up to ask you out and you laughed at him - he wouldn't realise you were shy, most guys don't.