Can someone explain this to me? (Harry Potter and the deathly hallows)?

The first person had the technically right reason he survived(having two souls and choosing to go back...or something like that) but I always thought that him technically possessing all three hallows played a role in it also. But with him not defending himself he made the spell to protect everyone at Hogwarts like his mother had for him. 8example(neville not dying when hit with the killing curse.)