-If he tries long range, Gai evades it and punches a hole in Kakashi's chest.
-If he uses intangibility, he gets blitzed when he stops using it to attack.
-If he goes to another dimension, he is basically running away.
It doesn't need to last 5 minutes, Gai can just redo the steps over and over again. Or he can just wait till Kakashi attacks to blitz him.
And EE only caused recoil in the beginning, Gai was able to continue doing it repeatedly after that, as seen when he finished the 5 steps with no interruptions unlike the first time.