These pictures show what a terror attack on a large shopping centre could like.
Anti-terror police swooped on the huge Intu Trafford Centre in Manchester in a staged training exercise which featured a mock suicide bomber detonating a device.
But there were some noticeable differences to a real life attack. The volunteer victims first went through a safety briefing where they were reassured that no live rounds would be used.
Then they were given ear defenders and safety glasses.
Still, it gave armed officers a chance to test their counter-terror tactics to test their response to a Paris or Brussels-type attack on civilians.
About 800 people were involved in the role-play exercise which started at midnight at the entrance to The Orient food court when a man dressed all in black walked in and shouted at the crowd.
Moments later an explosion rocked the food hall and volunteers - wearing their safety kit - dropped to the floor.
Many were made up to look as if they had horrific injuries and others screamed out as if in pain.
Smoke filled the entrance to the food court and some of the volunteers ran from restaurants, as if they were trying to dash to safety.
Police stressed there is no specific threat to the shopping centre and the exercise had been planned since last December, but it has given them and businesses the opportunity to test their emergency terror response.
The exercise, codenamed Exercise Winchester Accord, is the fourth major exercise in months, coming after previous ones in London, Glasgow and Essex.
Greater Manchester Police, the North West Counter Terrorism Unit and the North West Ambulance Service were all being tested as part of the exercise, with no personnel being told precisely how the "attack" would unfold.
The sound of gunfire could be heard ringing out through the food court as the volunteers screamed for help.
A mock masked gunman appeared at the foot of the steps near the entrance to The Orient, firing a number of shots.
The latest drill took place while the shopping centre was closed to the public between midnight and 6am on May 10.
The exercise will continue throughout the day in other locations in the North West, including Red Bank Community Home, a disused young offenders' centre in Newton-le-Willows, Merseyside.