Rather call it "insane", or "Stamina booster" mode. This will build you the power. Always include high intensity intervals in your training. In the Free Round mode you must throw as many punches as you just can. In a three min round try to accomplish over 500 punches.
An ideal training would look like 5 min Guided followed by 3 min. Free Round repeated at least 2 times and closed down by a 5 min. Guided.