I originally meant it to be just a hatch with a ladder that went down to the scaffolding that ran around the outside of the cargo bay, but you mentioned a crawlspace and I thought it sounded cool so I ran with it. It's a very short tunnel which has a ladder coming down into the second level (basically a catwalk) of the cargo hold. The catwalks run to two more ladders that lead down to the floor of the cargo hold which has a small hallway that leads to the engineering section of the ship which exists on two levels. The core and physical systems down below, and the control-room up above. The engineering control room has a mostly-opaque floor, but there's grating around where the core comes up in the center of the round room which could allow the belowdecks team to scope out the positioning of the ambushers. On either side of the engineering belowdecks, there are tight, small spiral staircases that lead up to the engineering control room.
