Besides the lab area, the remainder of the first deck consists of a control console, secondary control station, full bathroom with laundry facilities, two airlocks, and the connecting EVA prep room.
As with any airlock, before opening the opposing hatch, a properly suited person must enter, seal the airlock, and depressurize the space (or pressurize, depending on which direction they are heading). In the EVA prep room, the pressure suits are stored and the user suits up here. Before donning the outfit, a trip to the bathroom is recommended for short-duration outings.
For longer forays away from the Hab, there is a selection of diapers, collection devices, and undergarments for each crewmember – individually labeled by name, of course. And as someone will usually point out, while you are suiting up: whatever you do in the suit stays with you in the suit. Upon returning to the Hab, one might want to shower after being cooped up in the suit for a time, as sweat, body odors, and ‘other’ odors tend to build up in the enclosed space. And if two people have been out on an EVA, there is a second full bath with shower, on the berthing deck, one level up.
Elsewhere, there are two more hatches providing an exit outside of the Hab. The first is located in the floor of the first deck, just behind the ladder. This one requires closing off all deck admission to the ladder-well, thereby creating an airlock in the ladder-well, itself.
The remaining hatch is atop the Hab and is also accessed by sealing off all three deck hatches and decompressing the ladder-well. To reach this hatch, the suited crewmember would climb a stationary, rung-style ladder from the third deck. Because the Hab was wrapped with solar panels before liftoff: this was the crew’s entry point, through an opening in the coupling between the Hab and the booster. Once inside, the opening was sealed from the outside, in much the same way as the Space Shuttles or the old Mercury, Gemini, and Apollo capsules.