When Frank Kiveat collapses, the EMT states that his pulse is thready. His partner gets the monitor/defibrillator and the first EMT carries out chest compressions even though Frank is moving spontaneously (i.e. is alive). Then the ECG shows asystole (flat line) before they apply the defibrillator. You cannot use defibrillation on asystole. In addition, Frank appears to be conscious when Darin talks to him and clearly cannot be in full cardiac arrest.
As Mulder and Scully leave the morgue for the first time, they pass a bottle of amber liquid labeled "Acetic Acid, glacial" on the shelf. Pure acetic acid is colorless.