At the end of the episode, Felicity and Diggle are shown standing together, with a building and a straight road behind them, waiting for Oliver outside the prison. Felicity then walks towards Oliver, they kiss, the camera pans out for a long shot, and suddenly Diggle is nowhere to be seen in the area outside the prison which now has no building and the previously straight road has a 90 degree turn.
Oliver breaks out of his cell by combining gum, the gum wrapper, a 9-volt battery, and an aerosol can to blow the lock. Later, at the end of his fight with Diaz, he shuts the cell door and it locks in place. The hole is still visible, and there is no way the prison had time to replace the cell door.