HK Police appears to be utterly useless and incapable of handling the situation -- both on the streets of HK and in the airport. In any other country the airport situation would have been dealt with swiftly -- mass arrests and then blocking all entry points to the airport island, only allowing people with passports and boarding passes/confirmed flight itineraries to enter.
I get the strategy of selecting the airport as the site of these protests as it will garner more international media attention, and the risk of the police cracking down violently is smaller while the world is watching. That being said, given the developments of the past couple of days it appears to have backfired. Everyone I talk to these days are condemning the protester violence as absolutely inexcusable, and it appears Western media (at least non-Anglo media) have moved from portraying the events as 'freedom fights' to a more 'mob violence' angle in the past 24 hours or so.
My main concern at this stage is that the HK Police seems incapable of dealing with the situation -- I certainly hope they will sort it out and not call for 'back-up' from the Mainland, in which case thing could escalate quickly.