Most of those are sniper training techniques.
You don't know what is going on so go find out (recon being one of the major things, way more than shooting things).
Daydreams aka fantasies are a technique some are taught to stay on task when you are watching things for an extended period.
Something is wrong but don't know what is basically what we already covered.
Backpack full of rocks is a fairly standard ruck march technique.
This is why you are taught to police your brass.
Fairly solid plan and why they teach stealth.
Sit in one place for long enough and yeah weird to have a body.
Tricking people into thinking you belong there is a solid type of camouflage.
Constant self improvement is surely a goal.
Not eating, or eating properly, is part of the deal for long missions.
Best to weed that one out.
A high value target may appear there so best to be good at it.
Can't have it all so suck it up and deal with it.
Terrible decisions are best to be avoided/can't take back bullets.
Solid description of a sniper shot.
Possibly another aspect of camoflage or at least cover.
Messy room is surely a type of mind palace, something many use to do the whole remember a tray of objects part of the testing.
Out of communications. What else?
The few snipers I have met over the years have a darker sense of humour than any medic or policeman I have ever met and they skew ten times darker than the man on the street. Or if you prefer the famous response to "do you feel anything when you take a life?" of "recoil" largely sums that one up.
It is said that nobody likes a sniper on a battlefield as they are the only ones that set out to kill.