Is the USMC "crucible" safe?

Is it safe? uhm..yeah. Its an excersise to try and imitate actual combat environment. Ask the guys that did the Iraq invasion, 4-6 days with 20 minutes of sleep. living on smoking, chew and any form of caffine. Eat?> hell, no time. So yeah, they can handle 3 meals (MREs) over 3 days, 4 hours of sleep. a 10 mile walk back? thats the easy part.