Final answer:
The message that Hannah told her friends they must carry from this place if they survive is about the dangers and risks associated with the place.
Step-by-step explanation:
The message that Hannah told her friends they must carry from this place if they survive was not explicitly stated in the provided information. However, based on the given passages, it can be inferred that the message would be about the dangers and risks associated with the place they were in. The characters in the passages express concerns about safety, being killed by aviators, finding an underground way of escape, searching for their children, and making a try for themselves. These passages indicate a sense of danger and the need to be cautious and mindful of the risks involved.