The Meaning of Knife

OMFG, aliens are going to take over the earth! You sprint up to Sapien III, not minding any more security, and rush into his bathroom. You find him there. The first thing you notice about him is that he's missing a very necessary part of the male reproductive system.

"Well, hello!" he greets you warmly. "What are you doing here?"

"I have to tell you something. You practically rule the world, so you must defend it. Aliens are going to take over the earth! They are impersonating guards here! Even you are in danger!"

"Bah! The Bible says these things: there is no such thing as a Jew, homosexuality condemns you to hell, everything in the cosmos revolves around the earth, there is no such thing as the cosmos, Jesus died to save our sins, not because he was killed, and THERE IS NO SUCH THING AS ALIENS!"

Wow! That didn't work well. It looks like it's all up to you to save the world. Do you try to stop all of the aliens yourself or form a coalition of the willing?