If possible, enclosed areas should be ventilated for 20 minutes before anyone enters, and individuals should be equipped with a full-face mask and an air supply. The patient in this case died as a result of a normal bacterial process - energy production. The case was designed to teach you about bacterial energy production. The following exercise will familiarize you with bacterial energy production, and is more important than the particulars of nitrogen oxide poisoning. All life requires energy.
Bacteria are no exception.
For one thing, they need to synthesize macromolecules. Pyruvate is, in fact, central to most fermentation reactions, but lactic acid is not the only product. Alcohol, acetic acid, formic acid, butanediol, butyric acid and propionic acid are all possible products depending on the attendant enzymatic reactions. Many bacteria are identified by the fermentation products they produce. NOTE that in all these reactions, oxygen is unnecessary, as an organic compound is reduced while NADH2 is oxidized.