My point is: Gojo literally dont react to sukunas movement, when gojo say this "what?!" Sukuna ALREADY was on his back ( as we clearly is not seeing sukuna on his side, and gojo still was looking straight, to the exactly same place where sukuna was before even moving ), which means that gojo didnt react and he only perceived what actually happened when sukunas sure hit suddenly goes off and his domain is destroyed
And this doesnt make anysense if gojo reacted and actually knew what was going on, like, he "knew" and would be like " i mean, even though im clearly capable of reacting to what youre trying to do, im just going to let you destroy my domain for fun "?