I may be wrong, but I think dialysis patients are only deficient in B vitamins because dialysis strips them out, and most dialysis patients don't have a good enough diet to replace them quickly, which is why they give us renal multivitamins. If you take more than the recommended amount of B vitamins, they'll stick around until your next dialysis because you're not peeing them out.
Since the 5-hour/6-hour energy shots have such a high amount of the different B vitamins, you're pretty much overdosing. Normal people would peak at a probably-safe level, and quickly lose the excess in their neon-green pee. We dialysis patients don't excrete the B vitamins nearly as well, so they could peak at a much higher level, and stay there for a long time. Sounds dangerous to me.
Though, if you're still urinating, and it turns neon green after you take the shot, you might be safer.