I work on construction site in a connected container office. (In the west) I share a room with a female colleague. The door is always open and walls are thin so everything is heard. Coworkers are in other rooms and can walk in anytime. Is this considered being alone?

Imam Al Albani explained that Khalwah is being with her where no one can see you and walk in on you, so a door left open that people pass and can enter, and people can see you, remove it. However, the problem here is free-mixing and if this is happening, then it should be avoided.