It sounds more like a subconscious expression to me, than anything related to a past life.
Your mind may be expressing a deep fear of an inability to escape from some concept of danger.
Often doors won't open if the mind cannot concoct what is on the other side.
Try this: spend some time visualizing a safe, open place during meditation.
Start off visualizing you are there. Since the dream is an enclosed space, I would suggest an outdoors field, on a bright, warm, sunny day. There is freedom in every direction. If another type of environment works for you, then by all means visualize that.
Make it as vivid as you can.
Visualize yourself walking around in this environment.
The next step would be to meditate, and remember that place in the dream. Remember the doors vividly, as if you are in the dream. Force the door open in your mind's eye. It leads to the safe place.
Visualize walking through the door. Turn around. The door is gone. You are only in the safe place. You have left the other behind.