Ahmad Vaughan borrowed $50 000 from Sarah Jamal. The parties' agreement required Ahmad to repay the loan in monthly instalments of $1000. As security, Sarah took a mortgage over Ahmad's nightclub, which was worth $200 000. Unfortunately, because of the unusual nature of his business dealings, Ahmad frequently experienced tremendous fluctuations in his monthly income. What would be the likely outcome if, three months into the agreement, Ahmad received a large amount of money and attempted to repay the entire outstanding balance immediately? What if, instead, Ahmad suffered an economic setback and was unable to pay three consecutive instalments? If Sarah did not want to use her security to enforce repayment, is there any way that she could nevertheless sue Ahmad for immediate repayment of the entire outstanding balance? Explain your answer.