Lando... is an idiot. And obviously no one else in the Rebel Alliance was smarter as this suicidal order was not countermanded with what the Rebel Fleet SHOULD have done once they saw the Death Star's superlaser weapon was functional. I don't know if anyone in the Rebel Alliance noticed but you can't aim the superlaser except by moving the entire Death Star. All the Rebel Fleet had to do is withdraw behind the Death Star opposite of the side with the big death dealing weapon on it. I bet dollars to donuts the Rebel Ships can move faster than the Death Star can turn. They were just trying to buy time until Han could get the shield down. Wouldn't it have been better to keep the fleet intact behind the Death Star and away from the Star Destroyers that were just there to keep them from escaping?