In this phrase: 尾班車開出前5分鐘, is meant to signify “5 minutes before the departure of the last train”.
I find the structure a bit strange for me. In my mind, I would have thought of something like: 尾班車開出5分鐘前.
I am familiar with the structure: “event 之前” to mean “before the event”, but i am unsure how to create a phrase with added modifiers like time or place.
Please provided some insights.