In this hypothetical situations of choosing between your animal and a stranger, there is an underlying condition which is that you would (even if briefly) put yourself in danger to save your pet or that stranger. For example, saving your cat in a fire rather than a stranger. In reality, in most (all? I hope) countries, you don't have an obligation to risk your life staying in a building on fire to save someone; you could even be considered an obstacle to the professionals coming in. So you don't have to stay inside any second more than what it needs you to run away. You don't owe nobody anything. So... All of this to say that you would legally be ok if you use that second to grab your pet and run (realistically, the pet will be nearer you).

And this consideration can be applied to most of these hypothetical situation, considering that removing any animal or person from a danger require that you put yourself at risk in that brief moment ... This isn't something that is legally required to any person. What you describe is helping, but (example) you aren't required to jump from a ship to help someone, you only help them if you don't put yourself in danger.

The way the "pet Vs animal" scenario is presented is already intrinsically different than the omission of help scenario.