Basically correct. But so we're clear, the barricades around the Hill are not like the ones surrounding the White House: they're intended to block motor traffic, but not to stop pedestrians from entering the front lawn, which is public space.
Similarly, while there is security within the Centre Block, it consists of guards and metal detectors inside the doors. The building is a tourist attraction, after all. They can probably stop people from smuggling handguns or bombs into the building, but this guy actually rushed the doors, from what I understand.
I just heard Josh Wingrovefrom the The Globe and Mail, whose video shows the gunfight in the rotonda and the Hall of Honors, say that it appears that the gunman went through the side door, which he describes as not having metal detectors, so that the PMs and accredited journalist can get in and out quickly.
He is still not able to leave the building 6-9 hours later. He is with staffers and tourist, women, children and babies, who did not anticipate this ordeal.
I also heard that the construction workers who are working on renovations, used their scaffolding to get people out of the building.
Let us pray there will be no harm towards all that are trapped.
Growing up in d’Ottawa, I remember a time when, without wearing any visible ID, if you knew where you were going made your way to the Parliamentary restaurant, you could get a four course meal for less than the price of a Mickey D’s meal, a few years after Chartier blew himself up in a bathroom on the Hill.