Hard but not impossible. You train 6 hours per day in three 2 hour blocks with 2 hours in between. The training includes conditioning, striking and kicking, qigong, internal conditioning and meditation. Remember, you are not going to be going through anything the people training you have not already gone through. Times a thousand.
Safety is the number one concern. The combat in Combat Model is hard contact point sparring. Not full contact. This is NOT UFC and this is NOT bloodsport. You will be wearing protective gear which includes a face protector.