First off saying "Put your hands up or you will be shot" is a violation of rule 2.2 which states
(2.2) Random Deathmatch (also known as RDM) - Shooting at someone without engaging in any form of quality role play (eg. Giving enough time for them to comply with your order. Count downs are not considered quality roleplay, please at least attempt to create an interesting roleplay story before considering shooting.) is considered RDM. (Punishment is a ban).
This rule is not applicable in the red zone.
Also to add to this, from what I understand if someone threatens your life then you may defend yourself! But as @Its a Barkie stated it's called ROLEPLAY.CO.UK for a reason.