For a highly intensive, flexible programme like this, two trainers can do a much better job than one.  There are a number of reasons for this:-

• The course can be split into two for particular training exercises, one trainer with each group.  In this way, they can monitor all that is going on and give personal feedback to help people progress.
• Breaks and mealtimes on the course lead to a lot of personal discussion with participants.  Two trainers can obviously cover twice as many people, providing a more-in-depth experience.