Sneaking away from a box delivery point
The box delivery points are a convenient way to get around without the time and expense of a helicopter deployment. However, they tend to put you right on top of an enemy stronghold. You're usually in vision range of a guard patrol, and for some delivery points, you're completely surrounded.
How do you deal with that? Dive out of the box and crawl away while the enemy isn't looking? Just run for it? Have your buddy distract or eliminate the guards so you can get away unnoticed? I haven't tried all my ideas, but the attempts I've made so far have all been a lot slower or a lot riskier than I'd like.
One way would be to add a poster of a guard to the box. Hopefully you've come across these posters and picked them up, you can add a poster to your box by pressing the quick dive button while opening the item's menu.
Adding a guard will probably trick other guards into thinking that you are a friendly. If they are too close for this trick though, perhaps try to add a poster of one of the bikini girls or anime girls, they will run over to you thinking they just scored, at which time you can CQC them to your hearts content. (Remember that guards who are in close proximity to each other will allow you to preform a CQC combo without triggering a full combat alert.)
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The least-risky method I can think of is to use a buddy; D-Dog's bark is very effective, but the problem is you can only tell him to stay where he is, not go somewhere else and bark. However, if there aren't too many guards, you can probably take them out. Additionally, I think that it will only attract one guard at a time. Guards seem to have this behavior where only one will volunteer to go check out a suspicious noise when not on alert, even if it was noticed by several of them -- as opposed to on-alert behavior where they'll automatically tell any nearby guards to form up on them. They'll pay attention to the guard while he goes to check, but remain at a distance.
Alternatively, Quiet is a good distraction if you have equipped her with an unsilenced rifle (and don't mind sneaking around with the base on alert). Have her shoot someone; I guarentee the guards' attention will be drawn elsewhere.
A riskier but more effective method is to use decoys. You can throw decoys like a grenade, and activate them like C4. They're very effective and cause guards to walk right up to them for a close examination before they realize it's a balloon. It will also cause ALL guards to walk up to the decoy, not just one of them like the aforementioned suspicious noise. Right-clicking while in the box allows you to pop out of the top very quickly and begin aiming your equipped weapon. Usually, guards aren't looking at the delivery point even if they're next to it, so you should be okay to pop out and toss a decoy before hiding again. Just be sure to take out the guards inspecting the decoy if you don't want CP to be aware that you've infiltrated -- they'll report anything suspicious.
If you're going for takedowns, a viable option might be sleep grenades. They're quite risky to use but very effective. They have a fairly small radius, so be sure that the guards are all close together -- and be sure not to walk in the gas yourself! Also, if the guards are wearing gas masks, the sleep gas will be ineffective. However, they do take effect immediately on the guards and don't make any noise. If you plop it right in front of their faces, they might react fast enough and dive away from the gas cloud, though.