ExpressionQuestion to ask
fi ghadAt which time tomorrow?
fi al-masjidWhere does the act or effect occur?
fi dukhulikaHas the entry occurred?
fi mudiyyi yawmHas the whole period elapsed?
General rule: Fi retains a connection to containment, but the suitability of the circumstance and the nature of the governed event determine whether the relevant meaning is time, place, part, whole or condition.
Different legal consequences can therefore emerge from the same particle without arbitrary interpretation: the governing relationship differs in each sentence.