There's no such thing as "early" in the army, you're either on time or late. There are some exceptions to the "be early" rule, like starting artillery barrages for example, but these are unlikely to apply in most offices.
It doesn't matter what you do at night
Long drinking sessions were actively encouraged in our unit. There was only one rule: whatever you might have got up to the night before, you had to be on parade on time. No excuses. I've spent all night in the bar, changed into my uniform and gone straight (well, swaying) to the parade ground. This turned out to be excellent discipline for management "conferences".
The NCOs run the army
For those unfamiliar with military structures, NCO is short for Non-Commissioned Officer. NCOs are not particularly senior, but they are the ones who make things happen; the ones who stop their superiors from getting their men killed. Business examples could be the PA to the CEO, or the office manager. The good ones know everything, and everyone, and will do their utmost to stop their bosses from implementing the dumbest of their ideas. Be nice to them.
Sleep when you can
If you've been up all night digging trenches and lugging heavy weapons around in the rain it gets pretty tiring. Consequently, we learnt to grab a quick 20 minutes whenever we could. Back in civvy street, to the amusement of my co-workers, I would often have a nap under my desk if I was feeling groggy or if I wanted to be sharp for a big meeting. You may well feel like crap when you wake up, but you will always be better for it.
Training. Training. Training
Soldiers are not just cannon fodder. Over the centuries armies have learned that the best ways of organising a large number of people to act together, is discipline, and training whether it relies on repetition or initiative. The untrained are a liability.
Never volunteer for anything
For me, I think this should be amended to "never volunteer for anything unless you're sure you know what it is". If people decline to tell you what they want you to volunteer for, it's probably best avoided.
Guns hurt
I've fired many different guns (not very accurately, in truth) but only at targets and under strict army control. The idea that untrained people should be wandering around with guns for fun is ludicrous. I've seen a trainee shut their eyes and unload a 9mm pistol into the ground by their feet while the instructor cowered behind them. In business, don't over-burden people with the means to damage the organisation unless you're absolutely sure they can handle it.
Any fool can be uncomfortable
Spending all day (and night) outdoors means you'll generally be cold, wet, miserable, or all three. It's up to you to boost your own morale by making yourself as comfortable as you can - you get no extra marks for dying of frostbite rather than being shot. There's no such thing as bad weather, just inappropriate clothing.
Your Company Needs You!
So, if you have the chance to spend some time with the military I would recommend it, it's another world with much to learn from. Similarly, I think it makes sense to look favourably at recruiting ex-army types if you have the chance, as a Jack Reacher or two will transform any office. It's good to know you have someone who can handle an Uzi when the CFO comes visiting.
