[jsdkshffkas dammit sons why are you so sneaky this is totally unfair to mom!!!]

I didn't sneak in! Sneaking in implies something of a negative connotation, like I was a robber. I was...simply using an alternative route to enter the apartment. [Or, to put it more simply-] I didn't have my key and I didn't want to wake you, alright? Don't worry about it.