At times during Sundays 31-28 loss in St. Louis, where post-whistle shoves, scrums and trash talk often went unchecked by replacement referees, Redskins Coach Mike Shanahan said Monday that he worried the volatile atmosphere would boil over.Ive never been in a situation where you felt that there was going to be an explosion on the field, Shanahan said. Youre hoping it doesnt happen. It didnt happen but I thought it was very close to losing control.With the members of the NFL referees association locked out by the league in a dispute about pay and benefits, replacement referees worked the preseason and Weeks 1 and 2 of the regular season schedule.Asked if the absence of first string referees contributed to the mayhem at Edward Jones Dome, Shanahan said: You have to keep control of whats going on the field. Once you get used to doing something, you get very used to making calls, its second nature, you go about your business. Sometimes when you dont make those calls right away people do lose their composure.