Yeah, I like snakes too. I feel bad that I killed him, even by accident.
If I had known he was there, I would have got him away from the birds, but I would not have tried to harm him. I worry about my birds getting caught in the inner aviary door, but I never would have expected a snake to get caught trying to enter through the outer door! It freaks me out that I didn't even see it happen. He must have been right under my feet!
Fortunately, none of our native snakes are venomous and most of them just want to be left alone. They are not aggressive unless cornered or threatened. I don't mind having snakes around, so long as they steer clear of my little birds. Although they would likely be safer somewhere else, because my dogs, chickens, and peacocks will hunt them down without a second thought.
It is possible he was simply trying to get away from me and not trying to gain access to the aviary at all. Wrong place, wrong time. Bad luck for a long snake. I hope he didn't suffer.