If you happened to pass by Union Station in the middle of the night this past Saturday, you probably saw some seriously alarming and disturbing sights. 

Luckily, none of it was real. 

Metrolinx and Toronto Paramedic Services conducted their largest joint emergency exercise at Union Station in the early hours of November 3.

It’s a busy night here at Union Station as we prepare for the largest joint agency emergency exercise in @Metrolinx history. @AMAwithAMA @fannie_sunshine and myself are helping media get all the shots they need. pic.twitter.com/e2hjvpI8we

— Scott Money (@sMoneyON) November 3, 2019

It involved 150 actors, professional make-up artists, and staged smoke at platform level.

The simulation imitated a mass casualty situation at one of Canada's largest transit hubs, and it began with someone acting as a gunman shooting at passengers exiting a GO train.

A simulated emergency exercise is starting now at Union Station. The scenario begins with an actor dressed as a gunman pretending to shoot at passengers disembarking a GO train. @CityNews pic.twitter.com/eqS5Sqyh68

— Tina Yazdani (@TinaYazdani) November 3, 2019

Volunteers were covered in fake gunshot wounds, as emergency professionals tended to their injuries and treated the situation as real and urgent. 

*emergency exercise at Union Station* more “victims” in the Great Hall. Unbelievable seeing our first responders in action. They are going all out, truly treating this simulation like a real-life mass casualty situation. @CityNews pic.twitter.com/OwhV2ESlXw

— Tina Yazdani (@TinaYazdani) November 3, 2019

The simulation as a whole imitated a terrorist attack with 30 shooting victims.

Photos of the overnight @Metrolinx @GOtransit training exercise at Union Station. About 200 people, including first responders, actors, make-up artists participated. They simulated a terrorist attack with 30 shooting victims, and a fire on the train platform. pic.twitter.com/B9xtYNSUQZ

— Jeremy Cohn (@JeremyCohnTV) November 3, 2019

It also included a fake fire at track level, and fire trucks surrounded the outside of Union to address it.

Here’s a couple photos of ⁦@Toronto_Fire⁩ in action shots that have never been taken before

Responding to ⁦@Metrolinx⁩ Exercise fire trucks were safely escorted under track protection into Union Station Rail Corridor to response to simulated fire track level pic.twitter.com/inGyHIUa0R

— Bill Grodzinski (@GOgrodzinski301) November 4, 2019

The simulation included about 200 people in all, including more than 50 volunteers from four different St. John Ambulance branches.

St. John Ambulance @SJA_York Region #EmergencyManagement Unit supported @Metrolinx at @GOtransit #exercise at Union Station. Over 50+ #volunteers from (4) #StJohnAmbulance Branch’s deployed resources for the largest joint agency emergency exercise in #Metrolinx history. pic.twitter.com/F5WZp2TcXX

— SJA York Region (@SJA_York) November 3, 2019

"Safety is critical to everything we do at Metrolinx, and it is important to regularly test our emergency preparedness to ensure our staff and first-responders are ready in the event of any type of critical incident at Union Station," said George Bell, Metrolinx VP of Safety and Security, in a statement.

Hundreds of (fake) bloodied volunteers, dozens of transit officers, fire fighters, paramedics and police officers all ready to go for a massive disaster simulation at Union Station. pic.twitter.com/d8G1wKkRqL

— Marco Chown Oved (@MarcoOved) November 3, 2019

The emergency exercise was about as terrifying and realistic as a simulation could be. And though it may have looked horrifying from an outsider's perspective, it definitely showed how dedicated and committed Toronto's emergency professionals truly are to keeping the city's residents safe.