Sorry, if it has been discussed before, but I think I found out that Portal 2 does lack the general door (those which first Portal uses in bts-areas) models.

So, the real question is that how to use the push-door and the sliding door from Portal 2 underground section. They seem to have their movements animated, so I think prop_door_rotating isn't a good idea.

Could somebody please give me some advice with that? VDC didn't have anything about them.

In order to use the 'fire exit' door in underground you need to create a prop_dynamic of it and put a large button (brush) over the door. When you press the button set your door's animation to 'open'. If you also wanted the door to close by using it again then either use a logic_branch or a math_counter to set it to the 'open' or the 'close' animation.

Make sure to parent the button to the door so then the player can actually walk through the walkway.