Lights Out is a routine present in all prisons. It typically begins at night, though some prisons have irregular schedules. During this period, all cell doors will be locked with a yellow key, and are opened at the end of Lights Out. If you are not in your cell by 1 minute (1 in-game hour) after the start of Lights Out and you are caught outside your cell, you will be sent to solitary and it will become morning. If caught outside your cell after a minute and you have no Bed Dummy on your bed, you will be sent to solitary (no matter what outfit you are wearing.) Do remember to wear a Guard Outfit if going out at night, otherwise the guards will send you to solitary upon seeing you.
(If you dont have a Guard Outfit you will be instantly sent to Solitary even if you have a Bed Dummy on your bed)