When Saliari asks you to go around the restaurant, kill the gangster with the Tommy gun in the alley. Take the Tommy gun from him, then wait in the alley at the end of the stairs. Eventually about four to five gangsters will exit from the door. Kill them and take their guns. Don't go through the door. It is better to go around the street because the gangsters who's left will be looking towards Saliari and will not suspect that someone will come from that direction. Use the element of surprise. Note: Watch out for the gangster with the Tommy gun standing at the window that is above the door near the restaurant. The best way to kill him is not to go behind him; it is by going under the window and shooting him.