Even if it is all me, which it usually isn't, there is a very big difference in my mind between a scene and a situation. A scene to me suggests I have something I want to present to the group, as well as a strong sense of where it should go. A situation is something where I the GM can be just as surprised as the players by where things go. Generally the starting point of the campaign, obviously I as the GM have a strong hand in establishing (this is the system, this is the setting, etc). But the players make their characters and connect them to the setting. And once their feet hit the ground, they do what they want, which helps develop and prompt new situations.Umm, where did the situation come from? Who initiated the situation? Who set the location, the opponents (or allies or whatever is being reacted to)?
It isn't just about opening doors. It is about what the players are trying to do. I can introduce a local bully if i want, but the situation develops very differently if the players try to work with the local bully and take over the region, versus if they try to put the local bully out of business or ignore the local bully entirely. The player characters have their own agenda and that adds a huge element to the situations that arise.
I may roll for a random encounter, but I am going to describe it very differently depending on what the players do, it will play out very differently depending on what they do, and they can always interrupt me for clarifications as well. I am not saying there is no description, but I definitely don't see it as narrating a scene. I remember modules that used to be structured with scenes and I didn't like them. Not something I find helpful when I think of adventure and campaign structure.