You asked for this. What is it that you can "instant"? The least amount of time possible? And what's that? Picoseconds? (10^-12 seconds)? Actually, we can keep going. 10^-13, 10^-14, etcIt doesn't....Naruto fap boys would say anything to give their lord the advantage...not only is Minato a sensor but he's instant.
Anything that's not instant won't and can't dodge FTG....If FTG was an instant move itself that kills then Madara would be dead. Of course Kishi would nerf it some how.
Minato any form still > Naruto
His shunshin is even called his body flicker sometimes (by Rin)
and its instant:
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And how does FTG work? It's a space-time ninjutsu. Basically, it folds space-time to get the point A almost in the same spot as point B. Like a wormhole. So, the time FTG takes is: the time it takes to fold space-time, as well as the time it takes for the user to cross the "wormhole". How is that instant? If there is something "instant, that is.
You really wanna go this way? If not, I recommend you stop pulling "instant" out of your ass. Minato's movement after FTG is not instant, so people can react to it.