In the scene where Ecks is chasing Sever, you see Ecks put a shell into an open chambered shotgun. This means that there is only one shell in the gun. A moment later when he yells stop inside the building he cocks the gun again. Thus, he is holding up Sever without any shells in the gun.
In the video game Ballistic: Ecks Vs. Sever for Game Boy Advance, Ecks fights against a double agent called Agent Kaos. Kaos is the movie director's nickname.