Should any member (1) die while in the service of the City, and (2) leave a spouse, the said spouse shall receive a retirement allowance computed in the same manner in all respects as if the said member had (1) retired effective the day preceding his death, and (2) elected Option II provided for herein, and (3) nominated his spouse as joint beneficiary: Provided that, the retiremen allowance so computed shall not be less than fifteen per cent of the deceased member's average final pay. In the event of the remarriage of the said joint beneficiary his or her retirement allowance shall terminate: Provided that, if the aggregate amount of retirement allowance payments received by the said joint beneficiary is less than the accumulated contributions credited to the said member's account in the annuity savings fund at the date of his death, the remainder shall be paid to such person or persons, having an insurable interest in his life, as the said member shall have nominated by written designation duly executed and filed with the Board; and in the event there be no such designated person or persons surviving the said deceased member, then such remainder, if any, shall be paid to his legal representative. No payments shall be made under the provisions of this section to a beneficiary of a member in the event payments are made under the provisions herein pertaining to said member's death in the line of duty.