How clinical reasoning works

In a recent examination, students were given a scenario and then asked a few questions about it. Their answers show me how they interpreted the evidence.

A man suffers a pulmonary fat embolism and hypoxia after trauma to his legs from a motor vehicle accident. He is intubated and ventilated. His blood pressure is normal and stable. Subsequently he develops elevated levels of urea and creatinine in his blood. His serum potassium is also elevated (6.5mmol/L). His urine output is recorded as 450ml/day. His ECG shows sinus rhythm with frequent ventricular premature beats. His serum creatine phosphokinase (CPK) level in the blood is significantly elevated. His ABG shows signs of metabolic acidosis. His blood counts show a haemoglobin value of 10.5gm/dL, an elevated white cell count and a slightly low platelet count (130000/uL). His PT and PTT are normal. 

The students were asked:

What is the complication (apart from fat embolism) that is seen in him?

Some answered 'Acute myocardial infarction'.
Comment: These students got this response by looking at the ventricular ectopic beats in the ECG and the elevated CPK level in the blood. However they failed to take into account the lack of ST segment or T wave changes in the ECG. 

Some answered 'Sepsis with multi-organ failure'
Comment: These students looked at the elevated white cell count and the abnormalities in the lung and kidney to come up with this answer. They did not realise that elevated WBC count can be due to inflammation after trauma and that the lung abnormality is due to fat embolism. Sepsis is a possibility in this situation but, with the available evidence, we have no unequivocal evidence of sepsis yet. 

What is the correct way to reason and answer this question?
The rising urea and creatinine within a short period of time along with a lower than expected urine output suggests acute kidney injury. What could be the cause of the kidney injury? There is trauma and a raised CPK level. These suggest severe damage to muscles. Hence rhabdomyolysis could be a cause. It is also possible that he has hypovolemia due to loss of blood and that has contributed to the acute kidney injury but the evidence for this is not seen in the scenario. So, the answer to the question should be: The complication that he has now developed is acute kidney injury secondary to rhabdomyolysis. 

How will the ventricular ectopics be explained? The logical explanation for it will be: hypoxia from the fat embolism is the cause of the myocardial irritability.