Good you were able to get a re-entry pass. When you exited the 2nd time, did you go to the special immigration desk and they opened a gate for you to get to T3 baggage claim?

You must have been very tired from your flight since if you landed at B2, the escalator to immigration is very close, just past the transfer desk. In order to walk to T1, you had to walk past 8 gates (7 in T3 and 1 in T1) to get to the T1 immigration area. It's a long walk (I've done it before).

I'm guessing you were one of the last to exit the plane. Otherwise you would naturally follow the flow of pax exiting to immigration at T3.

Sorry it happened to you. A wasted hour isn't so bad. You now have a funny story to tell your kids and grand-kids.