A loud bang and a cry of "We're going in" were heard in the moments before an armoured vehicle rolled into a canal in Afghanistan killing four of its occupants, an inquest has heard.
Colour Sergeant Martyn Horton, from Runcorn, Private Douglas Halliday and Private Alex Isaac, both from Wirral, and Lance Corporal David Ramsden, from Leeds, were serving with the 1st Battalion The Mercian Regiment (Cheshire), when they were killed in the incident near Gereshk, Helmand, on June 23, 2010.
The soldiers were members of a police advisory team and were travelling as part of a two-vehicle convoy when their vehicle, a Ridgeback protected patrol vehicle (PPV) driven by Lce Cpl Ramsden, rolled into the Nahr-e Bughra canal.
David Ridley, coroner for Wiltshire, described how the incident happened as the vehicle was travelling to an incident at police checkpoint five (CP5).
He said: "The lead Ridgeback vehicle had just passed over a bridge, a loud bang was heard followed by someone shouting 'We're going in'."
He described how the vehicle then rolled down a steep bank and the four men did not survive the incident.
Lieutenant Colonel Paul Dupuy, who was the commanding officer of the Gereshk operation co-ordination centre district (OCCD) and whose task was to liaise with and mentor local police, described Gereshk as a busy city which was an important logistical hub for the local population.
He said his role was to train the local police force, which included setting up the advisory team which was commanded by Col Sgt Horton and included the other three deceased.
He said: "It had been described to me as incredibly dangerous where Gerensk was seen as a potentially difficult situation."
He said the risks included improvised explosive devices (IEDs), suicide bombers and direct attacks. His role was to help build relationships with the local police force which had 240 officers and up to 20 checkpoints.
He said: "There were significant challenges, one of these challenges was the police force was not a coherent organisation."
Colour Sergeant Horton, 34, from Runcorn in Cheshire, joined the Army in 1992 - seeing service in Cyprus, the Falkland Islands, Belize and Kenya, and on operations in Northern Ireland, Iraq and Afghanistan.
He was promoted to Colour Sergeant in June 2009, when he assumed the role of Reconnaissance Platoon Second-in-Command.
Following his death, his sister Caroline paid tribute to the loving father, brother and son, saying: "We will miss his cheeky grin. He will be fondly missed by everyone he knew and sadly died doing the job he loved. Once met never forgotten."
Private Douglas Halliday, 20, from Wirral, joined the 1st Battalion The Mercian Regiment (Cheshire) in 2008 and served in Northern Ireland, Kenya and on operations in Afghanistan.
His family said: "Dougie was deeply loved by all of his family and friends for the love and laughter that he brought into their lives. Dougie was always the life and soul of the party and will be missed by all. We are all extremely privileged to have shared his short life."
Private Isaac, 20, was also from Wirral and also joined the Army in 2008, serving in Kenya and on operations in Afghanistan.
After his death, his mother Annette said: "My beautiful darling son who was a fighter, and so brave, you will always be in my heart, my soul and my thoughts. God bless."
Lance Corporal Ramsden was 26 and from Leeds. He joined the Army in 2002 and served on operations in Northern Ireland, Bosnia, Iraq and Afghanistan.
He left the Army in 2007 to pursue a career as a civilian, but became a Reservist and deployed to Afghanistan in 2010 to advise the Afghan police.
Paying tribute after his death, his family said: "David lived life at 1,000mph. He loved Army life and his job, and as a teenager was in the Army Cadet Force.
"Although we didn't see much of him due to Army life, when he arrived back his personality lit up a room and we knew he was home and we will miss him so much."