Huh? 5G Lee's faster than Kamui, 5G Lee's slower than Juubito and Tobirama's reacted to Juubito. Kamui isn't too fast for Tobirama, not a chance. GK goes in one direction [Kamui is way too fast for that to happen. Kamui has no indications sign. If Tobirama's going to use Goju his initial reaction would be to escape the detonation range, which is huge, so how would he know when Kakashi's about to use Kamui at not only a distance, but with Kamui's extreme speed.
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], so as long as Tobirama is behind his Edo, he won't be in the range of GK.