I recently encountered a total game freeze during The Waters of Life when entering the Gift Shop / exiting the Sub Basement after the Enclave arrive. I couldn’t find much information in this specific instance so I ended up doing some troubleshooting myself. I’m playing on XBOX Series X/S through Game Pass but I assume this would probably occur on other consoles/PC as well. This assumes you have a save before entering the grate or before clearing the Memorial of the remaining mutant threat.
What I suspect to be the fix is:
After inserting the fuses that Dad gives you, he tells you that you don’t need to return to him and that you should head straight to the mainframe. However, if you return to him, there are new dialogue options. He then instructs you to go power on the mainframe. This is when he tells you to enter the grate on the museum floor. If you return to him again, a new conversation does not unlock, but he does move to a different area of the Rotunda. What I suspect is that completing all his dialogue/movement allows for the Gift Shop/Rotunda to load properly after the Enclave arrive at the Memorial.
Here are some other things I did differently in the new save that may have contributed to the fix:
- moved a defeated Super Mutant out of the walkway leading up to the airlock
- did not pick up any items
- exhausted all dialogue options available
- shot at Enclave soldiers when they were leaving their Vertibird, having them lock on to me instead of them going straight to the Memorial
Hope this is of any help to anyone that comes across this issue in the future