do not pay attention

"ignore the warning"

each one's blood is on his own head

Here "blood" represents death. The phrase "on his own head" is an idiom that means the person will be held responsible. Alternate translation: "it is their own fault if they die" (See: rc://en/ta/man/translate/figs-metonymy and rc://en/ta/man/translate/figs-idiom)