red, open towards the large circle. Exiting the ladder is easy, falling into the ladder is hard, the gate swings into the platform and you can back up out of the way without infringing on the big circle which may be the work area. If it is at the blue location it does not protect from falling into the ladder as directly and obviously. If the gate is at blue, a person can get to the small platform, get involved in a work item, forget where they are and fall backwards into the ladder. If you must have one at blue, put another at red.