"RDM is killing another player without any type of HOSTILE role-play being initiated and reasonable amount of time for the target to react."
If you are the target or tagged in a gang who's being targeted, RP is active by the belligerent. If you are not the target you must RP with the target and give reasonable time for the target to comply, as the rule stated above.
"Revenge killing is NOT a form of role-playing reasoning."
And of course, RDM rules do not apply to illegal areas.
Personally, unless you have people with you or you're geared, should GTFO from the shooting area.