I read a bunch of stuff about the TD and TDB and all that, and read alot of theories behind how the TD could possibly actually destroy all time and space and everything unless it had already done it in some otherwise possible timeline and whatnot. I came up with two ideas:
1) TDB/Tesseract/Whatever you wanna label it, seems like it should be one of a kind. Sure, each timeline/dimension has a bunch of trash barrels it throws events/people/etc into, but they all end up being dumped in one big 'ol dump anyway, right? I'm saying that there could very well simply be one TDB for all timelines/dimensions in the entire universe to use, and it has no additional timelines or dimensions of its own. It's just a one-of-a-kind heap of junk. So you get rid of something in TDB, it's gone; that's the only possibility, that's what happens/happened. Makes sense if you relate it to fighting Ozzie, Slash and Flea (note how their battle backgrounds are the same? Makes sense to me).
2) Belthasar really might've been playing it safe and decided to scare Serge and Co. Really, it's more likely not all that powerful. Schala's a tough little girl, but she's by no means more powerful than Lavos was on his own, so how could they possibly combine together to amass enough power to destroy everything and every"when"? Actually I think it was only just a REALLY strong version of Lavos that scared the daylights out of Belthasar, and what he probably MEANT was that it had the potential to spread everywhere and consume like our buddy Lavos was originally trying to do. The difference is Mr. TD would be far, FAR more successful, and would accomplish it quickly, having spent an unspoken amount of time (or non-time...o_O) in TDB gaining power and what-not, especially being a combined Lavos/Schala freakshow.
*shrug* Those make more sense to me than all the other ideas I've read so far. Then again I came up with them...^_^