Board Thread:General Discussion/@comment-25752308-20150121131432/@comment-34326521-20150131102237

KaizerBlazeX, erasing timelines is a tricky thing to do in every franchise/movie ever written (except one, but that's a subject for another conversation). A bomb to do this needs to be carefully calibrated. You can't just program it to look for Bens who had heard of the Omnitrix. The bomb is not omniscient. You set it to eliminate specific timelines that you know have Bens who have heard of the Omnitrix. And, obviously, you can't just change settings when you please. You need time.

Of course, this is all my speculation.