Deliberate mistake: After James and Kat enter Whipstaff and get the power turned on, when Kat heads to the staircase to go search for a bedroom, we can see a few of the metal stair runner rods attached to the stairs to keep the carpet runner in place. However, when James falls at the top of that staircase and gets rolled up in the carpet runner like a sushi, there are zero stair runner rods. (00:21:30 - 00:31:50)
Deliberate mistake: After Stinky delivers his "Smell-o-gram" to James, he trips over the vacuum and falls, then continues down the stairway, with his body rolled up in the stair runner as it gains momentum. The problem is when the sushi runner hits the ground floor, the runner's edge is facing the opposite way to what it should be; deliberately done for the momentum and to have it humorously unroll. It's entirely impossible for it to turn itself around and then still have even more momentum to unroll the way it does. (00:31:45)
Chosen answer: It was most likely Pneumonia, which was very deadly before the discovery of antibiotics.
Donald Jenkins