Yes, it seems it is established that those words were in the lyrics of the song you heard. I stated that those words may not have been the actual name of the song. When you say you were "watching" their concert, do you mean you "watched" it by means of a video of it and not in person and this video of it displayed the title of the song on the screen and it was labeled as "Kill Them All" (written as "them" not "'em" like the album)? edit: (sorry, missed that link and am checking it now to see if it can help me to help you find what you're looking for.)