The desperate man barged into Elmhurst Hospital's administrative offices and demanded to see someone in charge.
He took two executive assistants as hostages, leading them into the empty office of the hospital's chief medical officer with what appeared to be a gun in his right hand.
And as the man, known only as "Steve" to his victims, grew increasingly uncooperative, observers took copious notes.
Turns out this was only an active-shooter drill to test the coordinated response of police, firefighters, hostage negotiators and hospital employees, all while the campus maintained normal operations Wednesday afternoon.
The hospital must stage several drills a year under state and federal mandates, but voluntarily conducted the hourlong training exercise involving an active shooter played by Elmhurst police Sgt. Steve Mandat.
"This specific type of drill is not mandated, but with everything that's going on in the general world these days, we decided to be proactive," Dr. Michelle Meziere, the emergency department's associate medical director.
Mandat stepped into the role of the "bad guy" with a detailed back story for his character: a husband who wanted answers after his wife and "love of his life" had died from a heart issue at the hospital a day earlier.
"I want to talk to the boss," he told his mock hostages. "You have five minutes, or I'm going to start shooting."
At 1:30 p.m., he made good on that threat with a special training weapon that only fires blanks. None of his "victims" were hurt.
The episode ended a short time later with police arriving with their weapons drawn. One officer checked Mandat, slumped to the floor behind the office desk from what was supposed to be a self-inflicted gunshot wound, and detected a pulse.
Officer Jason Krueger told his team to secure the suspect and check the other offices and hallways to see if anyone was injured.
"We don't know if there's another suspect anywhere," he cautioned.
Paramedics then treated an "unconscious" Mandat and wheeled him out of the office on a gurney as the drill came to a close.
Both Meziere and police said the exercise -- in the works for several months -- went smoothly.
"I was very happy with the link up that occurred between the police and fire supervisors and the administrators of the hospital, so that the command decisions could be made quickly to take control of the incident," Elmhurst Deputy Police Chief Mike McLean said.
The police department had 20 officers participate, while the fire department sent an ambulance crew and a battalion chief as a supervisor.
"It's crucial that police, fire and emergency management work together to resolve the incident safely," McLean said. "You have to practice these things ahead of time so you're not stumbling later on if a real event occurs."
Hospital employees and first responders will collect feedback and evaluate their response. The hospital's emergency management coordinator will compile those findings in a report in two to three weeks. That assessment will help guide future training.
"It's a scary drill. It's all too real, but I think everybody did a fantastic job," Meziere said. "It will be a great learning experience for us."