That was lag, good old fashioned lag. Another tip for you is use aggressive ballistics on your last word, it gives it the ability to get 2 shot kills if one shot is hipfired and hits the head. It also 3 shots people on the body if it's hipfired. Your last word will always be a 3 shot head shot unless you come across someone with 0 armor, and it'll always be 4 shot body shot.