We are always practicing or meditating.
Practice is something we do all of the time. We have erratic or focused practice. Meditation is paying attention to silence while practicing. Even when playing music there is a focus on silence. The silence is what the music rests upon. Silence is the foundation.
Apriori is now unsure that he is learning about himself. King, he sees, is well into his own practice. The silence now leads Apriori to doubt. Doubt is a silent foundation to truth. The Dhamma is the protector because doubt removes obstacles. We may become despondent but with focused practice we become confident.
Practice is doing what we can do. By doing we grow in merit. By doing we grow. Our actions and the observed results increase our ability to achieve. It is up to us to make good of all of our actions.