Why Self realization is beyond mind and body?

Self realization is not an understanding. It is not something which we can understand.

What we take from our senses is our experience. For example, we see this world. This world is our experience. Self realization is not even our experience. It can't be taken from our senses. It is not 'something' it is everything. It is we ourselves, the real Self. As it can't be understood it is beyond mind. And can't be felt/experienced it is beyond body.

For example, a camera takes pictures and convert it to soft copies. Our body is camera and the pictures in it is our mind. Now, who is clicking pictures is different from the camera and pictures. If the cameraman says that the camera is mine there is no problem. But he says, I am the camera and had identified himself with it. When he clicks a good pictures, he becomes happy and a bad pictures he becomes sad.
He doesn't know that the camera has the ability to click pictures on its own.

He thinks that he is clicking pictures and converting it to soft copies. But in reality it is a magical camera that works on its own and the cameraman is just the witness of the actions happening.
Now the question is,
Can the cameraman clicks his own picture.

No. Because he is not even clicking the pictures. It is happening because of the nature of camera, it's magical.
This is an analogy for our real Self

The cameraman is us, the witnesser, brahman, Self, God. The camera is our body who is clicking pictures all the time, that is our senses working all the time and experiencing things. The mind is soft copies pictures which is like a processer of clicking which kind of pictures. Our senses are working on its own and mind is processing the information based on our senses, i.e. according to the previous information fed. It's all happening according the nature of the camera, i.e. the nature of our body.

The cameraman has identifed himself itself with the camera i.e. the Self has identifed itself with the body mind complex. So, the Self who is only a witness, believing it to be the body/mind and hence thinking itself to be the doer of all actions.

This all happens because the Self doesn't know who it is in reality. It is in the illusion of it being the body and mind like the cameraman was in the illusion of he clicking pictures, he being the camera.