If the copter in your photo is only 50ft in the air, then it is clearly
just an RC toy. Thus, I think you had nothing to fear.

If it is a full-sized aircraft, then it is clearly more than 50ft
(150-200ft would be my guess) - and you state that it was climbing
rapidly (probably had just taken off from a nearby field/lot). Again,
I don't see the problem.

-Pat