As an aside, I had a rental property in HK which I bought way back in 2008 (yea, really bad timing). Fortunately though, I had a HIBOR+ loan and when the financial markets tanked, HIBOR basically went to zero (sort of like where interest rates are now) so I was paying something like 0.2% interest on the mortgage
So while I was underwater for a while, really felt no urge to sell since carrying that loan basically came to about HKD800/month, or about the price of one semi-nice dinner for two in HK… ie. if the interest is low enough, even if the market tanks, you can simply ride it out