Yes, you do exit the box after maneuver 6. To perform the vertical upline you will fly straight and level, pull up through 1/4 loop, fly vertical (centered of course), then, push down through 1/4 outside loop exiting straight and level. You will now be at an appropriate altitude to perform the split-s. The double immelman is like 2 half loops with flat spots at the top and bottom. To center the double immelman you'll have to go past center before pulling through a half-loop, fly inverted (not sure what the required duration is), and then pull through another half loop ending at the same altitude that you entered. Keep in mind, if flying left to right the pull for the first loop will be to the right of center, and when you finish the 2nd half loop you will be left of center in order to have the proper geometry. Hope this helps, and good luck!