With two boats in a collision and fake blood splattered on the deck, it looked like something from a movie.
As passersby stared out at the scene on the Thames, blue flashing lights hoved into view from down the river.
The scene in Kingston on Tuesday evening was far from a disaster, but a preparation for a terrifying scenario which would hopefully never occur.
RNLI Teddington teamed up with Turks Launches for a rescue mission simulation to help both organisations practise how they would act if there was a collision involving a passenger boat on the Thames.
Starting at Town End Pier, High Street, the Yarmouth Belle set off toward Kingston Bridge before turning and lowering its anchor in the middle of the Thames.
Shortly after, the Thames Venturer positioned itself alongside the boat, getting as close as it could, with defenders positioned in between.
At 7pm, the emergency call was made, signalling the start of the training exercise.
The RNLI crew onboard the Yarmouth Belle.
Of the 42 people onboard the two boats, 16 were casualties and classed from priority one to priority four, based on the injuries they sustained.
Priority one passengers are those with life threatening injuries, priority two the seriously injured, priority three are walking wounded while priority four are presumed dead.
Over the tannoy on the Yarmouth Belle, the skipper says: "We have had a slight accident with the Thames Venturer. Nothing to worry about, but the emergency services are on their way."
A passenger with a leg injury during the rescue mission simulation.
As panic among passengers became apparent, with some crying out in pain, Turks Launches crew members checked the length of the boat, reassured passengers and fitted everyone with lifejackets.
"Don’t pull the red cord until you are in the water", I am told as a lifejacket is thrust over my head.
As I stand on the deck and look toward Kingston Bridge, I notice a passenger, albeit a dummy, floating in the water to simulate a man overboard.
Within minutes of the emergency call being made, an RNLI crew races along the river towards us.
As they approach the dummy in the water, they pull him to the safety of their lifeboat before climbing aboard the Yarmouth Belle.
The RNLI arrive at the scene of the mocked-up collision.
A command centre is set up on the deck, with an RNLI crew member co-ordinating the rescue mission.
Other RNLI crew begin to assess patients’ injuries before a triage is set up to begin treating some of those who are injured.
Shortly after a second RNLI crew arrived, we are told the Thames Venturer has become unstable and is taking on water, meaning an evacuation of the boat is imminent.
The RNLI take able bodied passengers to safety on the Yarmouth Belle before those with serious injuries are stretchered across to be treated.
Inside the triage, injured passengers are lying on the floor, oxygen cylinders are being used and RNLI crew are calling out for assistance as they treat those with serious injuries.
An injured passenger on the Thames Venturer being placed on a stretcher.
A time-critical passenger, the dummy that was thrown overboard, is taken down the river to the shore to be treated by waiting paramedics.
With treatment and evacuation in full swing, the skipper from the Yarmouth Belle makes an announcement to reassure passengers, some of whom are shouting out "I want to make sure he is alive" and "what can I do to help?"
Although the rescue mission simulation was finished within 45 minutes and I was back on dry land an hour after the mayday call was made, these exercises are vitally important for the RNLI and Turks Launches alike.
The RNLI crew heading back to dry land.
James Kavanagh, volunteer crew member at RNLI Teddington, said this week’s exercise was a stepping stone for a full scale exercise with Surrey Fire and Rescue and London Ambulance Service, which will take place in the spring.
Mr Kavanagh said: "What we focus on is the command elements of RNLI. When we turn up, we are looking to take control, organise the teams, get the triage going and help the priority one casualties.
"In a real situation we would have one boat turn up with one crew and a second boat would follow, but very quickly the other emergency services would turn up.
"Some of the people on the Venturer were very realistic. It forces you to behave in the way that we are trained to. We treat it as a real situation and we talk to the casualties, ask them their name and what injuries they have.
"The more we do this, the more it becomes automatic when it is real."
The Turks Launches boat, the Yarmouth Belle, used in the rescue mission simulation.
Richard Turk, from Turks Launches, said his company carries out training exercises each week and tries to work with the RNLI once a year for a large simulation.
He said: "We carry 300,000 people a year on five commercial vessels so from our point of view, safety is paramount. It is mandatory to do a very high degree of training and like most safety conscious companies, we go above and beyond what we need to do.
"It is great to do an exercise with the RNLI. Those guys are all volunteers and if we are going to call anyone out, they are the ones we would call so it makes sense to do a planned exercise with them to get the best training possible."