The status of your US taxes is absolutely irrelevant. You have broken the law of Hong Kong. You will be subject to the legal process in Hong Kong. You can expect a very hefty fine and, possibly, jail.
At the very least you will be prevented from leaving Hong Kong until l you can satisfy a court that you will pay the taxes due (including overdue fines) upon such terms as the court agrees. At some point you would have to look at selling property or whatever assets you have in order to pay, otherwise you could be a guest of the government here for quite a long time.
If you attempt to leave surreptitiously and are caught you will, of course, be jailed immediately for, if I read Cap112 s.77 correctly, 6 months.
And if you haven't already contacted the US Consulate you should probably do so - they can help you with a list of lawyers, and keep anyone you wish to be informed in the US up to date once you are in jail.
Emergencies - Consulate General of the United States Hong Kong and Macau
Legal Services Providers in Hong Kong and Macau - Consulate General of the United States Hong Kong and Macau