guards will shield will use them to defend against grenades... they actually will face the grenade, lower it to the ground, and brace for it
https://www.youtube.com/watch?v=uQ-5-xTzshs
in Africa, guards can actually have a conversation about it too if you're able to listen to 2 of them talk... they'll talk about how shields can be used to stop explosive attacks or just grenades... and also how or why shields are being given to troops and that there's not enough for everyone... it depends on their job (guard vs outlook vs patrol)
another small one... if it rains, guards can put out their hand to feel the rain and run toward nearby cover... was very helpful for me doing Mission 19... I saw that the intel team was forecasting rain when I was trying to stealth through the big mining camp, and a lot of the guards were too in the open... so I waited until it started to rain, and a few guards ran about 5-10 feet away to under a ledge or tent, and it helped clear a path for me to sneak through
a cool little one is that some of the mission or side op units are unique and actually have unique faces or names, and can be a unique option for combat operations, too
e.g. the Mission 5
or the Master Gunsmith... the former has unique eyeglasses and the latter a beard, and technically you can do a mission with either of them. Or, the first Wandering Mother Base Soldier is named Komodo Dragon and always has Climber; Jackal always has Athlete (he run's extra fast). The Mission 15
, Mission 3
gets the code name Silent Mastodon and Gunmen ability, or Mission 10
have the same unique face for everyone, too.
it's a kind of cool gameplay detail because it has more unique story flavour to an army that has a lot of 'random generics'
so, someone like Jackal or Komodo Dragon are sort of very minor Diamond Dogs, in a way, or someone like the bionic arm engineer Silent Harrier with the eyeglasses or Silent Mongoose with the big beard are kind of cool or unique ways to do free roaming...
it's a bit annoying to have to keep adding unique engineers to Combat Unit ;p cuz the auto-sort removes them every single time you re-open your iDroid... but I've been using Silent Harrier a bunch recently as a sort of 'gadget guy,' destroying outposts or tank/armoured units in as creative-as-possible ways using no guns, just mines, C4, explosives, grenades, etc
Jackal is fun too cuz he runs so fast
sadly, there are some combat restrictions... so, a lot of these unique characters cannot go on dispatch missions. Silent Harrier, Viscount, etc. also, the Ground Zeroes ones like Zhang Tian, Silent Basilisk cannot Dispatch or go on combat operations (non-playable). The Finger and The Eye also cannot go on Dispatch missions, though you can play them at combat operations (and the one even wears his aviator sunglasses).
i think the rule is.... perma-contract locked characters (e.g. Zhang Tian from GZ) cannot do combat operations (non-playable) or dispatch missions; characters that start as contract locked (e.g. The Finger, The Eye, Viscount, or Silent Harrier, the 'Gunsmith') can go on combat operations (playable) but cannot do combat operations..
i think related to the mission or side op source that they're from: e.g. the Africa interpreter can do dispatches because technically, if he died, the 'Recruit the African interpreter' SIDE OP will spawn again. but if The Finger or The Eye, or the bionic arm engineer Silent Harrier die... you cannot get them again
something like that at least because there's definitely a mix of characters that can do combat or dispatch, some can combat but not dispatch, and a few cannot combat nor dispatch, and it seems related to how their recruited and whether they start auto-direct contract or are perma-direct contract
