We did activate all 5 panels in order (1st set, then 2nd set, then the last one) but I cannot confirm this is required. We also had another possible bug when grappling from the platform to the tower (3rd grapple point). The first person seemed to fall down to a lower ledge which you could still grapple to the 5th panel from but from our experience you need to be on the higher ledge to be able to reach the final door. We could hit the final door grapple point but it would bug out and place us back where we grappled from when doing it from other spots beside the upper ledge on the tower. On our final successful attempt I (the sorcerer) was stationed on the upper panel of the second set of panels. As soon as I activated my panel I ran down to the tower and grappled it just behind another guy. He fell down to the lower ledge but I stayed on the upper one which allowed me to reach the door.