In the opening, at about 02.00 as Voight walks over the wreckage to speak with Mouch Christian Stolte the sign for W Monroe St can be seen. At 02.48 however, an item of clothing is draped over the sign.
Officer Bell reads a message, from April at Chicago Med, to Platt telling her that her (Platt's) Hepatitis test is negative. A hospital/nurse would NEVER leave a message regarding someone's medical information. Only the patient is allowed to receive that information. This is a violation of the federal HIPAA privacy laws. April faces termination and she and the hospital could face a civil law suit from Platt.
Mouch Christian Stolte is shown as part of the fire crew attending the blaze, but there is no sign of the rest of the crew from Firehouse 51, nor is Engine 51 or Truck 81 visible.