Simply put, "in pocket" means you can see your mark and know what your mark is doing, hence making your actions as the observer smarter and safer; "out of pocket" is the opposite, creating a potentially uncontrolled environment which is always a liability.
"Subjects are taking the ordinance off the plane; ordinance is in pocket in a black SUV, parked; primary target is out of pocket, presumably inside the plane. Awaiting visual confirmation of target."
Jay: Yea, BUT ireallii lyk her..
Tyrone: Maaaane she got u "in pocket"!!
Jay: Naaaah mane dnt no chik get jay in pocket..
Tyrone: Pssshhh yea wuteva!!