Uhm, Tobirama probably knows too, but how can he release it, when someone else is in control of him and thus limiting his actions.
When edo tensei was released, all the summons were given some time to act with their own free will. Madara was free to do as he please, as we saw Dan also was free to do as he pleased. This is why he could release the jutsu, and it explains, why he didn't release it earlier, as it could be risky. But when it was released, he knew the one who summoned him, had been defeated.