Underneath the Legislative Council (LegCo) building in Admiralty lies a so-called "secret tunnel".
Intended as an emergency route, it connects the building's carpark to that of the government offices next door.
But the tunnel also proved to be a nifty escape route for Hong Kong legislators who want to evade protesters or reporters lying in wait at the LegCo building's usual exit.
The tactic came to light last November, when some legislators went underground to avoid the crowds which had massed to rally over the government's rejection of Hong KongTelevision Network's application for a free-to-air licence, local media reported.
It incurred outrage, and on Jan 14, the LegCo Commission, which oversees the operations of the legislature's secretariat, made it official: the tunnel should not be used for evasion purposes.
After a meeting to discuss guidelines for its use, Legco president Jasper Tsang Yok Sing said it should be used only when lawmakers' security is at stake.
"If a lawmaker... wanted to avoid protesters or the press, it is obviously not a security reason," he said.
To outsiders, the issue may seem like a bit of a storm in a carpark. Why shouldn't legislators be allowed to enter and exit the building unmolested by protesters, the media and the public in general?
In Singapore, for instance, access to MPs within the Parliament House is tightly controlled for security reasons. They use a carpark that is sealed off from the one used by the public, and there are separate entrances for MPs and members of the public and the media.
Of course, this does not mean that they are not accessible to the people. Outside Parliament House, MPs - whichever party they are from - get up close and personal with constituents who petition them for help at the weekly Meet-the-People sessions.
In Hong Kong, however, symbolism at the legislative seat of the city is particularly powerful.
As the South China Morning Post put it, the "escape route raised concerns that it offered lawmakers a way out of their accountability to the public".
Said legislator Charles Mok, who represents the IT sector: "They should not be allowed to escape public scrutiny."
Beyond that, the abuse of the tunnel linking the two buildings - one housing the legislature and the other, the executive arm - speaks of the lack of separation of powers between the two, Mr Mok added.
An over-interpretation of the significance of one secret tunnel? Perhaps. But here in Hong Kong, it matters.