Good read here
http://www.agulnicklaw.com/articles/duty.html
Criminal Liability for Failure to Rescue: A Brief Survey of
French and American Law

Like Batman said "I don't have to save you" smile unless I own the property you're drowning on, or I pushed you in, or I'm your parent, or I'm your lifeguard, or I started to rescue you, or I'm in Vermont or Massachusetts and I can help without exposing myself to harm.

smile