Guild Wars 2

So I followed her up to the door and then she mentions that the door won’t open. So I jump down thinking maybe I need an EMP grenade or something which I take and as I’m going back up, the door opens and closes with nobody inside. We were able to complete all the other objectives in time and this prevented us from getting our achievement. I wasted 4 hours because of this.

You need to go in with her when the door opens. I’ve gotten the achievement and it’s basically that you need to “escort” her the entire time. I don’t want to give spoilers but it’s not bugged as far as I know, you just need to stay with her the entire time. For the achievement, only those that go with her will actually get credit for it, others who are trying to complete the other objectives will not get credit though the party will get credit for finishing all the optional objectives as long as one person goes with Caithe.