The south door, called the Catholicon, was the only entrance to the church in Margery Kempe's time.  It was guarded by a Muslim sentry who locked it from the outside.  Pilgrims were conducted to the door, granted granted entrance and then the door was locked for the duration of their vigil.  Kempe's experience, which she describes as from the evening of one day to the evening of the next, appears to be longer than the normal pilgrim's stay of evening to morning of the next day.