Actually, we do not know that Deck 8 is in the Engineering Hull. We just know in "I, Mudd" that the Aux Control Room is on Deck 8. As to the Aux Control Room, this is what I see when I look at it. The forward bulkhead is vertical. The strut has a curve to it but it doesn't give any indication to what is beyond the bulkhead. Good observation that they went down a ladder to check out engineering. Some items to consider: We do not know exactly where the beam in point is because: It is not identified. When Scotty and co descend down the ladder, we do not know what intervening decks they passed through to appear in the engineering room's upper level. They do not exit from same type of ladder they descend in. When Kirk and McCoy goes toward the camera we do not know where that part of the hallway leads to or what it looks like. When Kirk and co decide to go look for the Aux Control Room, they start back again at the beam in point and move to the hallway on the left (or exit, stage left). We again do not know what intervening hallways, turns, or even deck changes occur before they reach the Auxiliary Control Room. We can assume that the beam in point is somewhere: Above the Engine Room. Possibly between the Auxiliary Control Room and Engine Room Where is the Auxiliary Control Room? "The Doomsday Machine" - ambiguous as we don't know what exact path was taken, the starting location and the end location. "I, Mudd" - ambiguous as we know it is on Deck 8 but do not know what is around it. Norman's pass down the circular hallway may or may not have been on Deck 8 as we do not know what path he took after he walked by McCoy and Spock. Also, this room looks different than the one seen in "And the Children Shall Lead". "And the Children Shall Lead" - room similar to "The Doomsday Machine". Ambiguous location. Hallway greeble visible from open Aux Control Room door is not present where Kirk and Spock later end up and Chekov goes to arrest them. We again do not know what intervening paths were taken between exiting the turbolift and also when leaving the Aux Control Room to be arrested by Chekov. "The Way to Eden" - room similar to "The Doomsday Machine". We get to see more of the hallway outside the room and it looks like a tight U-shape. Unknown location. "The Changeling" - room similar to "The Doomsday Machine". We do not know what is around it due to cuts between characters leaving the room and when they show up in a different corridor. At best we know that Auxiliary Control is on Deck 8 but where exactly we do not know. Also, the room underwent a few cosmetic changes.