Consider a container that is partially submerged in water as shown in illustration at the bottom of the question. A, B, C and D are valves, that are currently closed. The container is full of water, because before the experiment we pumped air out of it through valve D (let's pretend that the air pressure outside the container can push the water up in the container above the valve A under these circumstances - also the container is secured in its position as pictured).
The experiment proceeds as follows: we open all four valves at the same time and observe what happens. The question is - will the water during experiment flow through valves A B or C out of the container, or will the air rush into the container through these valves?
In my opinion the latter is correct - the air will rush in through all valves - I imagine the situation is the same as having low pressure zone below the container. However, the water surrounding the container makes me a bit unsure - does it affect the results of the experiment?