When Paul Kellerman confronts Danny Hale in the alley, he draws his gun with his left hand. In the next shot, his gun is in his right hand, which he then transfers to his left.
When Michael checks the corrosion of the air duct under the infirmary the previous day/episode, the duct is made of standard aluminum material. In this episode, not only is the repaired "air duct" upgraded to industrial grade steel and now resembles plumbing more than any type of air duct, but even so, it would have taken longer than a day to rip out and replace all that aluminum and replace it with the industrial steel.
Michael climbs up a rope tied to a sewer grate to get into the room that is near the infirmary. However, if the rope is tied to the sewer grate, and he is hanging from that rope, how does he lift the sewer grate?