The 45 minute sell out implies that people had 45 minutes to book. However, as we know, the site was slammed immediately and it took 45 minutes for Google to fall over itself trying to process. It was effectively sold out immediately.
Given the number of tickets available (~4K I think) and the something like 1k+ hits/sec they had, the tickets would have been gone in a few seconds if the site had held up, not in minutes or hours.
