Come on, give me a break.
Is this world so worried about being sued you would not cut a guys foot off to save his life?
I guess dead people don't sue, right? Just the families, but then its not a direct testimony.
Any boy scout could cut a guys foot off and have them survive.
All you need is a rope, a stick, and a saw to cut with. A second stick is optional so the guy does not bit his tongue off. It was done all the time in the civil war.
Sadly, liability is always an issue. As a DM it's something I think about every time I dive with a non-pro. Fortunately I have never been in a scenario even close to this one.