Exception 3 deletes the requirement for a separation (both rated wall and opening protective) between the open-ended corridor (aka breezeway) and the exterior exit stairway where the two elements meet. In other words, a door is not required between the open exterior stairway and the open corridor (breezeway). If Table 1020.1 (per Item 3.2) requires a rated corridor (occupant load served by the corridor >10), the separation from the interior is required