the king’s garden - The “gate” to it from the upper, city above was appropriated to the kings alone; stairs” led down from Mount Zion and the palace to the king’s garden below (Neh 3:15).
two walls - Zedekiah might have held the upper city longer, but want of provisions drove him to flee by the double wall south of Zion, towards the plains of Jericho (Jer 39:5), in order to escape beyond Jordan to Arabia-Deserta. He broke an opening in the wall to get out (Eze 12:12).