This is a moment where he have to make a choice
Confession or not?
Confession right now, maybe he might get less beat compare to later on when she find out later
Not confession could mean beat the shit out of him thinking he is pervert looking at it for long time.
There is also third possible, as she didnt realized it yet, there is very likely she still didnt realized and wear something over it(like going to sleep etc)
Nice angle tho