I could see the survival instinct as a type of craving for becoming. But we can change instincts, just like we can change habits. It’s within our power to change and cultivate our mind the way we want it to be.
Even Buddha had the survival instict I suppose.
He went on alms rounds seeking food, he took medicine when he was ill and he avoided the dangerous situations.
In other words Buddha also experienced the feeling (vedana)
What Buddha did not have was the Thanha and Upathdana.
If we take survival instinct as Anusaya (latent dispositons) then Buddha did not have them.
It is definitely hard wired through eons of conditioning and that is why it is so hard to get rid of. IMO it is not biological but originates solely due to ignorance of not realizing what one is all about. If it is biological, then there is no way to overcome it other than through biological means.
I see survival instinct as reflexive. Like rapidly drawing your limb away from a red-hot object that it unexpectedly contacts. Or getting that burst of adrenaline like for example if a tiger jumps out of the jungle in front of you or you just stop yourself short of falling off a cliff. Or something really basic like holding your breath and getting that urge to breath. I think an arahant would still do and experience these and similar things, but they would do so mindfully and they wouldn’t be accompanied by mental defilements like delight and lust, fear, clinging, etc. Craving for continued existence is something we add to basic experiences like survival instincts because of our ignorance.