wander around the flat

You wander around the flat.
You go in and out of the living room.
You go in and out of the kitchen.
In the bathroom, you stop and have a piss.
You leave the bathroom and stand in the hall.
You can hear pop music, coming very quietly from next door.

do you:

put your head against the wall and listen to the music

hammer on the wall and shout ‘Keep it down’