dragon's spire

I just entered Dragon's Spire by the hole in the side of the mountain. I put the letter in the drop box for the dragon guy. I tried to keep going down the hall but that brass dragon head is burning me up. I tried to go out the same way I came in but when I hit the lever switch the door won't open. I hit the lever switch again but now both doors are closed and I'm stuck in the room with the bridge. I tried going below the bridge but I didn't see anything there. Did I miss something? I did save my game before going in so that's not a problem. I also finished Shurugeon Castle and received the shroud so I'm pretty sure this is where I'm supposed to be.
Thanks

Calm down, dont panic (and stop bashing me with that sword)

you cannot get up the passage with the bronze firedragon until your lead character is wearing the Dragon armour (stout mines)

The exit door is too close to the lever and standing in front of the lever means the door swings inwards, hits your party and closes again. Stand clear of the door or operate the lever and hit the 2 key and you should be out