Solution:
This question is a brain teaser or riddle, not a literal situation requiring a solution. The answer is that the woman shot her husband with a camera, not a gun. She holds him underwater because they are taking underwater photos. Finally, she "hangs" him by putting the picture on a wall to dry or hang, not in the sense of executing him. Then, they go out for dinner. The play on words is intended to mislead the reader into thinking about a violent scenario, while in reality, the actions are all harmless.