Today I watched just the end of the movie I Am Legend (SPOILER WARNING) and as the movie ended, one nagging question was running through my head: Why the hell would someone pull the pin on a grenade, and then just hold it? I know that it's supposed to be an emotional scene and all, but it's not like that was Robert Neville's only option. He could have waited until the zombie broke a hole in the glass wall, thrown the grenade, and then went with Anna and Ethan in the escape way they found. I realize that the writer made him kill himself to symbolize how he had dedicated his life to finding the cure for the virus that killed 90% of humanity, and that this film isn't exactly realistic. But no one would be that stupid, especially not a brilliant scientist.