Thought:
MOM is doing a masterful job of asking each witness connected to LEO how they became involved; why they became involved; if they liked their job etc etc.
All these wanna be cops have had a dream and had worked to make that dream come true. Z was in the process of doing the same.
To protect your family ( which prompted him to get a gun) and your community is a calling he heard.
Mom will do ok with the prof if not hit it out of the club house !
Like a master chess player, he's ten moves ahead of the witness and prosecutor.