Since you don't understand what people mean by latency issue, I'm gonna make it very basic for you.
You, the server or your opponent had a bad internet connection causing your screen and his screen to show completely different things.
The truth is, your guy was never actually safe but it took longer than usual for the input to be uploaded (Due to slow internet) and then subsequently downloaded to your ps4. If you've ever played a FPS online you will have experienced the "But i was behind a wall!!!" Same thing here, your character was still in the open to him.