Deffinatly not infantry. Now on day 12. 30 days without a shower I think I'd loose my toejam or I'd just accept it and be like screw it. And I'd really smell......and I'm not killing red guys tonight. Damn baby doesn't understand my addiction 
No showers isn't that bad. It does suck but when you have other priorities it really does not come to mind. In those situations you are glad to get any sleep, water food etc. The sleep sucks pretty bad too. Getting past no sleep is the toughest for the 20 hour-40 hr mark. Your body really wants some after the first 20 something hours sleepless. Once you get past the second day you kind of settle into a cycle of crashing and being full on alert. The trick is managing the crashing part so you don't screw up when it can kill someone you were not intending to kill, like yourself and team members. After the first couple days you do really have to pay attention to the decisions you and those around you are making too. Your brain skips the whole, is this really a good idea after all part of the equation. Your judgement and coordination gets on par with a drunk after a while. The same goes for many days with sub hour per day sleep. After a couple weeks of that, it takes a lot of self disciple to stay on mission.