I did not try this thing I will tell you after doing this but I think its not possible
Under water and in water are two different things. You may not cry when in the water but you can when under water. An individual in a submarine, a ship may be under water and can cry. If you just stand below a water tank, you are under water and there is nothing to stop you from crying.
Really finding it difficult to answer and another question crept into my find while thinking about this question in process...Can we smile under water?? and believe me if we can smile under water then surely we can also cry under water and if we can't then let's forget the question altogether....