Why would all the dreams be so similar?
Your Brain is searching for a solution to prevent dying. Your Body is flooded with adrenaline,dopamin, serotonin etc.
There is a reason for that, you are in a realy bad situation, you are dying. Maybe you where in a similar Situation in your live and prevented dead..that is what your Brain is looking for, a solution. (evolution, if you survive you replicate)
If you give your brain substanzes like serotonin and other stuff, you will remember things that you thought where long forgotten, Déjà-vu's and flashbacks from where you where young. Your brain is triggert with chemical substanzes that is how it works.
Your brain tries to remember and that realy fast, that is why all the dreams be so similar.