THERE IS NO EXTERNAL REALITY TO CONSCIOUSNESS.
Friend: Try running into a door..,
Reply: The body running into a door and bleeding is not evidence that there is a reality external to consciousness.
Of course the body running into a door is ample evidence that outside the body there is a door.
But it is not evidence that there is a door outside of consciousness.
As long as you are identified as a body, anything that happens to the body seems real to you, seems to be happening to you.
You are invited to examine the belief that you are the body.