AD in the elevator.
The elf elevator, also known as the elf chamber, is a location in Problem Sleuth. It is reached by exiting Pickle Inspector's office through the window instead of through the door.
When Pickle Inspector first visited this room, he had no idea it was an elevator. Upon entering he found an elf guarding a switch, and also possibly secrets. However, PI lacked the pulchritude required to ask the elf for wishes, and had no choice but to abandon the room.
When PI flooded his office, water poured into the elevator, causing the poor elf to drown. This was tragic, but later when Ace Dick arrived in the elevator, it meant nobody was there to stop him from throwing the switch, granting him access to the control room.