Look at the example below
The patient had died before the doctor came.
My teacher tells me that we use past perfect only when there are two events in order. The more past takes perfect form and less past takes simple past form. Like in this example the death of patient happened before Hence it is more past --> Past Perfect form. The arrival of the doctor happens later. So, it takes simple past.
Is there any instance when we use past perfect in a sentence to describe one event? Or do we always need two events?