Have to remember to yell "Drop the gun!" ,"Give yourself up!", etc. at the bad guy.
If you hear a voice behind you saying drop it, will have gamble that it is a cop and not a bad guy (turning around holding the gun to check out to confirm it is a police officer might be unhealthy) and drop to the ground and hope 1) It really is a cop and 2) the cop can deal with the incoming fire from the bad guy.
Yes, talking constantly and loudly about about who you are, why you have a gun, and what you are trying to do would give the arriving officer some information they would otherwise have to infer from what he or she was seeing. Of course, obeying their directions would reinforce the notion you are one of the “good guys.” (And I don’t think it would be that much of a gamble to trust that the voice behind you is a police officer - assuming they properly identify themselves - because an active shooter in that position would, well, just shoot you.)
They are probably still going to treat you with suspicion and secure your weapon but maybe you can avoid having them just shoot you out of hand the moment they come upon you.