You have to remember that Brady was also under pressure on that throw. He had to get it off or he was going to get sacked. I don't remember who it was, but one of the Colt LBs came through and Brady just had to find someone.
Someone else made the point that if you are going to go for it on 4th down, you have to run it on 3rd down. 4th and 1 or less is a lot different than 4th and 2.
Pretty much the only good decision on that entire series was to go for it. How to go for it, the plays called, the mis-management of timeouts, were all ****ed up.