We already know it's not running off main, or even linear time though. The way it seems to go down, Lavos lands and the Pocket Dimension is created, and Lavos begins eating. One "second" later someone (Zeal) starts stealing his energy, so he comes out and busts some caps. Goes back and continues eating. Right when he gets back, someone tries to summon him, but it's interrupted, so he shrugs it off and continues eating. One "second" later he decides he's full, so he comes up to bust some more asses in the Apocalypse.