The initiation chamber is where your spirit guide (your inner plane guide- an ascended master in training) activates you. The chamber receives information from the higher self of the incarnated person and displays the spiritual progress of the incarnated person on a screen to the spirit guide. The screen displays the progress much like a thermometer. The mini light activations received by the incarnated person are from the spirit guide. The spirit guide cannot send light to the incarnated person's higher self until the incarnated person completes a mission on earth. The higher self requests the light and the spirit guide sends the light. The light is filtered by the higher self to the level best for the incarnated one and the higher self then delivers the light to the incarnated body's nadis/meridians/nerves and the light adjusts the DNA and activates more strands.
The major activations, called "initiations" are approved and administrated only by a full ascended master (like Saint Germain) and Sanat Kumara or Lord Buddha.
Here are examples of initiations: http://www.scribd.com/doc/23828522/Ascension-Experiences
Major initiations are administered with rods of initiation. The rods of initiation activate the "fohat" or spiritual fire in the incarnated person and bring purification to the individual, remove more of the veil of separation, and unify the individual more with Shamballa.
Once the Eighth initiation has been completed, the individual converts from a physical density into an etheric density and enters the inner planes. Upon arrival in Shamballa, the individual is guided to the appropriate Ashram of a master (Rays 1-7) for further training. The individual may volunteer to become a spirit guide or continue service in some other capacity.
More on initiations in this document: http://www.scribd.com/4238979-Alice-a-Bailey-Initiation-Human-and-Solar/d/22694007