It was late at night and you were peckish..

You sat up and put your slippers on and snuck down to the kitchen to get a piece of bread or something..

Hotch on the other hand.. woke up without you in his bed.. and he got immediately into FBI profiler mode.. on instinct.. he got up.. got the gun from his drawer and snuck downstairs.. not seeing you anywhere..

he then got to the kitchen and saw you.