I don’t think the final incarnation of the MK plans have it overlapping itself. However, the queue is on the upper floor and entire ride is on the lower level. Mummy is a roller coaster which takes up a lot of room, and you travel through much of it at a fast speed. MK is a busbar dark ride that moves slowly. I would compare it to something like ET instead, which the MK building is a similar size. But, unlike ET, it doesn’t have to share the space with the queue and preshow, since it has two levels.