Okay, you and your best friend are out wandering around in the middle of nowhere and you stumble across Osama. Before either of you can jump him, he points an AK at you and reveals to you his Master Plan of Evil[sup]TM[/sup]. His agents (all dead now, BTW) have developed a virus that attacks only the brains of people who aren’t whacked out muslims like him. He shows you a vial containing the only sample of the virus and tells you he’s going to release it very soon to kill everyone on the planet who isn’t as devout as him. To ensure that no one is able to develop a vaccine against the virus, he’s killed all the developers involved with making the virus and destroyed all their notes. He boasts that until his scientists had developed the virus, no one even knew such a thing was possible, and now, because he’s killed them, and destroyed their notes, no one will have any idea of what’s killing people until it’s too late.
Of course, you know that since he’s told you all of this that he’s going to kill you shortly. He becomes distracted for a moment, and you and your friend jump him. It’s a titanic battle, and just when it looks like your goose is cooked, your friend manages to kill Osama. After riddling his body with bullets (to make sure he’s dead, you don’t want any silly “second grab” moments like you’ve seen in horror movies), your friend picks up the vial containing the virus, sticks it in a pocket and says, “You know, I think I’ll hang on to this. It might come in handy some day.”
What do you do? Do you let your friend walk away with the vial? (You can tell by your friend’s expression that there’s no point in trying to reason with him/her.) Do you pick up the AK and order your friend to destroy the vial? Do you shoot to wound your friend, and while he/she is thrashing about on the ground, take the vial from them and destroy it? Do you kill your friend and destroy the vial or do you kill your friend and keep the vial for yourself? Or something else?