Deck 1: Command
The forward section contains the bridge, main computer, captain's office, and quarters for the officers and marines. Moving aft into the central section, we find the mess hall with the galley just aft and the recreation room across the central corridor from it. Port and starboard are the forward gun turrets, with ammunition bays just aft of them. The central section is bisected by a large corridor with 4-person airlocks at each end. Aft of that are quarters for the engineering staff. Aft of this corridor lie main engineering and the aft gun turrets. The aft section contains the main reactor and hyperdrive.
Deck 2: Medical
The forward section contains a berth for one of the shuttles and the upper cargo deck. The central section contains quarters for the science staff and, to port, the sickbay complex, including a surgical suite and the ship's cryogenic berths, intended for freezing seriously injured patients until they can be returned to Earth for more advanced treatment. At the aft end of this section lies the lower deck of main engineering. The aft section contains the fission reactor, fuel storage, and hyperdrive.
Deck 3: Science
The forward section contains a berth for one of the shuttles and the middle cargo deck. The central section contains a corridor with the ship's five main labs ringed around it. In the very center is the biological containment lab, with its own life support systems unconnected to those of the rest of the ship. The containment lab is accessible only by two 2-person airlocks leading from the medical and zoological labs. The aft section of the ship contains the maneuver drive.
Deck 4: Technical
The forward section contains a berth for one of the shuttles and the lower cargo deck. The central section contains the ship's sensors and the engineers' workshop. The aft section contains the maneuver drive.
Two parallel lines in a wall indicate a door (note that in the hold and shuttle bays, these are often very large). In the gun turrets, a similar symbol represents the autocannon, but that doesn't mean that the turrets double as airlocks! The external doors in the cargo hold aren't airlocks, rather they are large hatches intended to be mated to similar hatches on other ships or orbital facilities for loading and unloading. Each cargo deck can also be depressurized and loaded from vacuum, if necessary.
Three faint parallel lines in a corridor indicate a ladder to another deck. Unfortunately, these didn't scan very well. There are two sets in the middle of the central section on Decks 1 to 3 and two more at the aft end of the cargo hold on Decks 2 to 4. There are also several lifts in the hold for moving cargo and ground vehicles around (not shown).