I wouldn\'t think it is possible to update and play at the same time. What the updater does is replace existing PS files on your hard drive with updated versions from the server. If you are playing the game and using a file as the updater is trying to replace it, one of two things is going to happen:
1) the updater will fail, because the file in question is in use
2) the file will be replaced, and the game engine will freak out because the data in the file does not match what it expects to see, given the version of the file when the game was launched.
You would probably be able to download the game and play it without running the updater, though you would be missing some fixes and updates that others have, which might cause problems in and of itself.
