It can. It just doesn't always do it first time. I think its about a 1 in 3 chance. I've had to use symbol of mana on occasion because the 9 shots I got from a full head of mana didn't open it. Climb it normally and only use 1207 if there is a reason it has to be open.

It also can shut again instantly, so use a macro to cast and go simultaneously. You don't want to have put 70 mana into opening it and have it swing shut on you before you get through.