Should the Lessee due to war, civil commotion, fire, earthquake, flood, act of God, or any other cause beyond its control, including but not limited to expropriation by the Government, be prevented from the enjoyment of the Leased Unit for the purpose intended, or be obliged to give up possession thereof, the rental hereinabove agreed upon shall abate during the time that the Leased Unit is not occupied by the Lessee