If the person initiates roleplay with you as usual and doesn't just RDM then it is allowed. To quote "you are no longer in a safe zone"
From your description it sounds like they broke: (2.2) RDM - Random Death Match Definition: Shooting at someone without engaging in any form of quality role play (eg. Giving enough time for them to comply with your order) is considered RDM. (Punishment is a ban)
It would depend if they successfully roleplay with you. If they threatened you within greenzone and shot you as you left I believe that wouldn't be allowed