Well I agree with INXS that she's made a mistake by not honoring her contract, she's a grown up and committed to stay there 14 months. But when she signed her job contract, she kinda had to get an apartment in order to live here right ? She didn't expect to loose her job so quickly, and not everyone has the chance to be able to pay 8 months rent for nothing.
When you're in your home country, most of the time you're entitled to unemployment allowances, which she obviously cannot get here in Hong Kong. So she doesn't have a choice and must go back. It's a shame for the landlord in this case, but in many other cases they're still better off renting to foreigners (every Chinese landlord I had in Mainland China preferred renting to me rather than to local Chinese) ...
Guarantee is there to mitigate this risk.