There is no duty to act.
Duty – is there even a duty to act?
Misfeasance – use the Reasonably Prudent Person test
Nonfeasance – No Duty
EXCEPT:   1. When nonfeasance becomes misfeasance
2. Created Risk
3. Promise – Quasi Contract
4. Special Relationships
2.    Restatement 322 – Duty to Aid Another Harmed By Actor’s Conduct
If the actor knows or has reason to know that by his conduct whether tortious or innocent, he has caused such bodily harm to another to make him helpless and in danger or further harm, the actor is under duty to exercise reasonable care to prevent such further harm.

Restatement 324 – Duty of One who Takes Charge of Another who is Helpless
One who, being under no duty to do so, takes charge of another, who is helpless adequately to aid or protect himself is subject to liability to the other for any bodily harm caused to him by
a. The failure of the actor to exercise reasonable care, to secure the safety of the other while within the actor’s charge OR
b. The actor’s discontinuing his aid or protection if by doing so he leaves the other in a worse position than when the actor took charge of him