Floating Phenomenon 2

After seeing Ronald being able to answer the question in Floating Phenomenon , Issac Newton was inspired and thought of a brilliant idea. He had decided to prepare a brand new lesson on fluid mechanics with his students. He quickly set up the following apparatus shown above. (refer to the bottom section for a clearer description on the apparatus)

Now, he says, "Class, I am sure from our previous lessons we all know the formula $P=hpg$ linking depth, gravitational field strength and pressure due to the fluid column as well as its relationship. However, I would like you all now to think creatively about this...." He paused and continued, "As seen in the above apparatus, the test tube is not moving at this particular height, but here's the biggest question: if we pour more water into the beaker, what do you think it would happen?" As usual, Ronald answered confidently. What about you?

Details and Assumptions :

-In the diagram, the immersed test tube has an open end that is facing downwards and an air bubble is trapped in it.