More on Evacuating

Still not sure if I totally get this, but I think Obama just said, “If you’re not evacuating when you’re asked to evacuate…” which loosely translates to:  ”If you’re not shitting when you’re asked to shit…”  

Who’s with me?  


From watching The Wire, I know there’s a correct use for the word “evacuate,” but I’m really struggling with this.  Can someone teach me when I’m supposed to laugh because a newscaster accidentally says that a person is shitting out a building instead of saying that people were forced to leave the building?