I think self preservation needs to be the prime motivation, at least from a logical perspective.

Heroism is appropriate when personal objective ethics and morals appear in a crisis and warrant a noble sacrifice or grave risk however.

Almost everyone would be heroic for the benefit of their loved ones, including their pets -- horses, ponies, dogs, cats, etc. I love my cat.

I will protect and defend anyone within reasonable bounds where it is morel likely that I can assist them than it is likely that I will suffer injury to myself. That is the Masonic Creed.

A small risk of injury is not necessarily a bad thing. An overwhelming risk of injury with no likelihood of being able to intervene successfully is rash however.