Okay, so I just rewatched that part to confirm, and there is a split second between 20:49 & 20:50 where his eyes are open!!! 
EDIT: Wait. I think I just got what you meant. Sorry for being so confusing! But there was a part in between where he takes his eye things off, and then it transitions to his masked Kakashi face. And Iruka had his eyes closed before the eye thing, but open after. It could be possible that he opened his eyes in that part when the animation was focused on Kakashi, and not him
EDIT 2: I rewatched that part again, and Iruka looks at Kakashi right after he takes his eye things off. Just before they are peeled off, the animation goes back to us looking at Iruka, and he has his eyes open. Can’t confirm whether Kakashi’s mask is on or not because of the scarf, but if you pay close attention, there is like a couple of seconds where we don’t see Kakashi’s face, and he kind of moves a little, like he’s still fiddling around with stuff; and then we hear a noise that could be interpreted as him like sliding a mask into place just before he practices his voice again. It’s so ambiguous, so it could be interpreted any way