RelationExampleQuestion
Timefi ghadWhen, or in which part?
Placefi al-masjidWhere does the act/effect occur?
Actfi dukhulika al-darHas the required act occurred?
The key question is whether fi merely specifies a circumstance or makes the occurrence of the named event a condition of legal effect.
Spatial suitability, temporal extent and completion of a named act are different investigations. Correct interpretation requires keeping them distinct.