Firearms officers descended on a Southend-on-Sea flat on Saturday afternoon following reports of gunfire - only to discover the commotion was caused by a video game.
Paramedics and an air ambulance also rushed to what was believed to be a serious incident.
A concerned member of the public had dialled 999 after hearing what sounded like shots being fired and someone shouting "I've been shot".
The armed response team arrived at the property in Sherwood Way prepared to break down the door using heavy equipment, including a chainsaw.
However, officers quickly established that the alarming sounds had originated from a resident playing the popular video game Call of Duty through powerful speakers.
Essex Police confirmed that no weapons were present and nobody had been hurt.
The emergency call was made in good faith by a genuinely worried neighbour, Your Southend revealed.
Although officers stood down rapidly once the situation became clear, the Essex and Herts Air Ambulance had already landed at nearby Bournes Green Park.
The armed response team arrived at the property in Sherwood Way prepared to break down the door (file photo)
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The helicopter crew had positioned themselves there in case urgent medical evacuation was required.
A spokesman for the force said: "We were called with concerns a person may have been injured with a firearm at an address in Sherwood Way at about 3.35pm on Saturday, April 18."
They added: "Armed officers quickly attended the scene with the support of emergency service colleagues and confirmed no firearms were present and no one had sustained any injuries."
This is far from the first occasion when a noisy entertainment system has triggered an armed police response.
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Officers quickly established that the sounds had originated from a resident playing Call of Duty
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In 2016, seven officers surrounded a property in Great Falls, Montana, after receiving two separate emergency calls about screaming, explosions and gunfire.
With weapons drawn, police observed flashing lights and heard loud voices from inside.
The source of the disturbance turned out to be a family watching The Walking Dead with their windows open.
"We had a whole bunch of guys on that one," said Police Sergeant Brian McGraw.
That same year, three firearms officers from Surrey Police responded to reports of a stand-off in Hampton Wick, southwest London.
A passerby had not realised they were witnessing a film production using replica weapons.
Helicopter crews had positioned themselves nearby in case urgent medical evacuation was required
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Director Tarryn Meaker said: "We had a sign up at the window to say filming was in progress but at one point it was taken down so maybe someone saw something they didn't like.
"I feel bad someone might have been thinking there was a serious crime going on,."
While just days ago, shocked locals in Toronto, Canada, believed a huge attack was underway when a fireball lit up the night sky - only to discover the blast was a controlled explosion on a film set.
Essex Police's armed unit responded to around 14,000 incidents during the past year.
This included 285 spontaneous firearms deployments and resulted in 336 arrests.
Remarkably, the unit has not discharged a weapon in public for more than 10 years.
The last such incident occurred in 2015 when a firearms suspect was shot in the leg and detained - itself was the first shooting in more than three decades.
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