James -
I believe we both share an interest in comprehending EM clearing more fully. Your description of witnessing, as used in EM clearing, as increasing one's trauma capacity makes sense to me.
A metaphor that comes to my mind is like afterburners that boost a jet to faster speeds. John does seem to describe witnessing as something that boosts a person's ability to process adverse subconscious material better. And, that would be an increase in one's trauma capacity.
But I am a lay person. Hopefully John will respond.
-Dean