Zombies in the apartment.

If the both of them weren't running, they'll have to start looking for another apartment where they'll spend the night. Another apartment its tap and shower were running 'cause they needed to take their baths before going to sleep.

It isn't easy to be journeying for hours and slaying zombies along the way, sweats would be produced and tiredness would enter. After all these, after they weren't bitten by zombies, they needed a nice freshening up.

Would I say their hearts were beating a little as they stood close to the tap and shower glancing at them? Yeah. It could be either two things, the tap and shower wouldn't be running, or they'll both be running. And they needed it to be running...but there was still a possibility that they wouldn't be running...it was making them a little afraid.