Ships often run a type of circle route between various Asian and west coast ports. So if a ship runs between Seattle and Pakistan, why stop twice in Hong Kong both coming and going? That would waste time being piloted into and out of port, loading setup and shutdown, etc. so often it can be more efficient to just stop once. A lot of the cargo isn't very time sensitive.
They would be dropping off cargo at Hong Kong & picking up cargo for Pakistan and other ports. They drop the cargo off at those ports and pick up cargo to go back to Hong Kong and ports East.
On the trans Pacific ships I sailed on we hit most of the ports twice.
I can see much of the port area from my office in the Seattle Municipal Tower. The only signs of unusual activity I see are a couple of helicopters hovering over the area. Oddly, just the other night I had a dream of seeing several explosions in the waterfront/downtown area, as I looked out my office window.