My Daughter is an emergency room nurse - I worry about her health a lot... That said, I'm sure health care folks are engaging in gallows humor right along with the rest of us.
During my lifetime I've tried to lighten most topics up with humor - or my attempt at humor - never with the intent of diminishing the seriousness or hurting others.
I think it's a human response that attacks frightening issues in an attempt to make the issue less ominous.