Sloth's regen doesn't matter in the slightest. Big T will splatter Sloth across the ground as many times as it takes. It's not like Sloth can hurt him on account of being too weak and too slow. And then, Toguro may even be able to cut the process short and just suck out all of his souls. Save himself some time and almost some effort.
There is seemingly no 'perfect' way to truly say goodbye. So I gathered a bunch of them!