Frederic, the Heroes workouts are a different animals. You curse when you read them, you curse when you do them, and you curse for days after them. They're supposed to be hard. All the pain you feel while doing the workouts reminds you that you're still alive to do them. Cherish it.
Accordingly, they fall outside the "try to get this done in a certain time frame" mentality. The goal is to finish. If you can do it as rx'd, great. If not, give what you can.
As for partitioning...read the comments and articles about Lt. Murphy. Murph intended this workout to be done between the runs, however possible. If you want to do it like Angie, great. If you want to do it like Cindy, great. If you want to do all the squats first, great. But if you have ignored the comments and say it HAS to be done a certain way, then you get to name your new workout, post it on "CFPC workouts," and we'll do your workout tomorrow. Today we do Murph.
You have 2 miles, 100 pullups, 200 pushups, and 300 squats to do. There aren't many corners to cut here. Figure something out, fight through it, and honor a fallen hero.