Avoid fleeing to the behind? OR Keep safe from the behind? – Project Management from military’s point of view –

There are many books related to Project Management in the world. I admit that PMBOK is an excellent theory. But I think it is difficult to apply it to the actual projects. I will give you one solution to this problem from the military point of view. By the way, which do you think a wall behind you is to avoid your fleeing, or to protect your back from the attack behind?