Subconscious, Meditation, Mindfulness via WHM Cold training (5.5)

What exactly is the subconscious? Is it a part of us or something totally separate? A bit of both it seems because we are living in it but are a complete separate entity from it. Meditation strengthens the bond and control we have with our subconscious.
How do you meditate or be mindful? Is it better to do so in pure peace or within an environment that tests you, safely of course?
Does utilizing cold for example like the Tibetan monks or Wim Hof create a hostle environment for tbe subconscious, an opponent, in regards to its crafty cunning abilities to distract and completely release and divide us from the NoW (our only dimension we have full access to at the moment)?
My discussion point here is on how to prevent subconscious sabotage and how to make it an ally.