OK, this might be a shock to some of you.
You're not obligated, legally or morally, to risk your life, limb, or property to save another's, unless you voluntarily accept that obligation.
No, but you are obligated to save someone, if there is no risk involved (e.g. you just have to switch a trigger to turn a machine/electricity off).
No, you're not. No obligation can be created that forces action, without voluntary acceptance of that obligation. I'm obligated not to turn on the switch that kills you, but not obligated to turn on the one that would save you.
To illustrate this, what is the first thing you would say to someone who
had flipped the switch to save you?
"Thank you ... for not neglecting a very obvious responsibility you have, unlike some that try to uphold some very childish beliefs about radical freedom"
"Thank you ... for have the mental capacity to figure out that if action or inaction has such grave consequences you do have an obligation and it being "forced" has nothing to do with anything"