If you are stuck between the ceiling and the bunk bed, you will not be able to climb out of the bed and you will be stuck. The first thing that you need to do is to slow down your breathing. It will make it easier to stay calm and think clearly. The next thing you need to do is examine your surroundings. What can you see? Are there any existing holes in the bunk bed? Can you find anything that you can use to help you get out? The best thing that you can do at this point is to call for help. Hopefully, someone will be able to hear you and find a way to help you out.