The chessboard in Dr. Nichols' apartment is set up incorrectly; the knights and bishops are reversed.
While watching the surveillance video Nichols points that the criminal is carrying the tarp that was used to carry the victim out of the building on his roll around cart. Then just a very short time later he is seen carrying the rolled up tarp with the victim inside. The implication is that he brought the tarp in to the building and very quickly used it to carry the victim out of the building.
This conflicts with an earlier scene where he points out a dust outline on the floor where the tarp had to have been laying for a significant amount of time due to the amount of dust on the floor.
This conflicts with an earlier scene where he points out a dust outline on the floor where the tarp had to have been laying for a significant amount of time due to the amount of dust on the floor.