Morgue

Meant for long-term storage of dead bodies, it's usually pretty empty. It has the only other Medbay entrance onto a main corridor and with the Chef, Chaplain, and Botanists also having access, those corpses practically walk out the door themselves. All those tasty genomes make it a popular attraction for any changelings as well. The dozen morgue trays and a small number of expandable body bags are the only items in here.

Since the cloning machine (and hypothetically Hydroponics) means that death doesn't have to be permanent, it's almost solely used to hold the original bodies of clones. '''The lights on the morgue trays indicate the state of the soul within the body. If there's a green light, it means there's an active soul. This generally means the body is waiting to be cloned or for something else to happen.'''

Basics of Body Bags
So you're most likely in Medbay, surrounded by uncloned bodies and husks. These are quite unsightly, and sometimes bleed all over the place to make the Janitor's job even harder. Not much of a complaint, you say? This also makes the area severely unorganized, potentially making it hard to distinguish the dead from the unconscious-and-in-critical and making it more likely to "accidentally" shove a dying person into a disposal because Medbay staff is too lazy to clone them anyway. What do you do to prevent this? Examine each body: If they're dead, bag 'em! Body Bags are found in boxes near Genetics, Robotics, and a few other parts of the station. To use one, pull it out, lay it down, drag the body onto it and click to seal. No muss, no fuss, no problems, right?

He's Dead, Jim
Body Bags are good for identifying dead bodies, right? Not always. Body Bags can be utilized for more nefarious deeds. If a poor assistant, traitor, or clown finds themselves on the run from the Law, they'll want to hide. Hop into a body bag and chuckle softly as your pursuers likely mistake you for a dead body waiting for cloning. Not even the mighty AI can penetrate your "High Tech" stealth solution unless it witnesses you entering the bag. Remember though, a body bag disguise will (likely) only work if done an area where you're likely to see one (Robotics, Medbay, Genetics, the Kitchen if your Chef has odd tastes, maybe the Chapel). A body bag can store multiple bodies as well, allowing you to kidnap a large number of braindead people or corpses at once.

Bring Out Your Dead...?
So if you're the previously mentioned Chef making a meat run from Medbay or the Morgue and unzip the body bag to find something distinctly non-corpselike (some examples: Syndicate agent gear, a live body, a husk from a Changeling's meal, Ian), just stay calm and report it to the proper authorities (unless it runs off on its own).