What happens when someone shouts 'man down'?
In 2007 in Afghanistan, 19-year-old Private Chris Gray was killed in a Taliban ambush.
"Suddenly there was an almighty eruption of fire - and I mean a co-ordinated ambush," says Lieutenant Bjorn Rose, who led the tours of Royal Anglian Regiment, 1st Battalion, in Helmand Province.
The young private was injured and his gruelling evacuation to a waiting helicopter was captured in graphic detail on the sergeant's helmet camera.
The BBC has been given unprecedented access by the Ministry of Defence to this footage and thousands of hours of other film shot on helmet cameras and personal video cameras by soldiers.
Our War - Ambushed is on BBC Three, Tuesday 7 June, 2100BST and will be available afterwards on iPlayer.
28 May 2011