Agonal breathing is when someone who is not getting enough oxygen is gasping for air. It is usually due to cardiac arrest or stroke. It's not true breathing. It's a natural reflex that happens when your brain is not getting the oxygen it needs to survive. Agonal breathing is a sign that a person is near death.
Yea I wasn't expecting it. I saw the other comment saying it isn't true breathing but fuck I would at least try and put them out of their misery. Even if he was functionally dead already.