DreamWorks Dragons Dawn Of New Riders Answers for Playstation 4

Stuck in Havenholme Ruins?

I finished the Havenholme ruins and am up to the task to fly to Valka's Mountain. I went back into Havenholme ruins to get one last chest that I'd missed but am now stuck and can't get out. Does anyone know how I can get out? I've tried completing it to the end but the last room is closed and I can't open the door. I've also tried walking back out the front door but I'm unable to access it!