Benzo overdose --> intubation --> airway trauma --> pneumothorax
(A) Aspiration PNA is possible with individuals prone to loss of consciousness, but would not be so acute! She was intubated then crashed 20 minutes later.
(B) Kerley B lines are indicative of pulmonary edema
(C) Pericardial effusion is characterized by Beck's Triad of hypotension, distended neck veins, and muffled heart sounds. And would not explain unilateral diminished breath sounds.
(D) pleural-based hump-shaped density probably describes a Hampton hump, which a wedge-shaped opacity in peripheral lung with its base at a thoracic wall. Caused by pulmonary infarction.