Everyone is running the north gate approach because that is what the first video showed. It works, but it costs you roughly ninety seconds waiting on the second patrol loop, and that is the difference between gold and silver on the timer.
Come in from the east breakwater instead. Swim the last forty metres, climb the maintenance ladder, and you land behind the first camera arc rather than in front of it. From there the whole east side is a single guard on a fixed path.
Timings that matter: the crane operator looks left every 22 seconds. Move on his second look, not his first — the first one is shorter and you will get clipped.