The Great Conflict

With the paralysis attachment on your energy pistol you wait until one of the guards gets close and then you hit him with it. Instantly, every muscle in his body freezes and he falls harmlessly to the floor. His fellow guard mate hears the thud and runs to investigate and before he can yell out for reinforcements you loose another shot and he falls to the floor harmlessly as well. With both of them paralyzed, you are able to suffocate both of them and drag their bodies down to the catacombs to avoid detection. It seems like no one as noticed your entry. You still have the element of surprise.