A court heard that a singer with the Cornish sea shanty band Fisherman's Friends and their promoter were crushed to death when a faulty 2.5 tonne door collapsed on top of them.
Trevor Grills, 54, a vocalist with the 10-piece shanty band and 44-year-old promoter Paul McMullen were killed by the heavyweight door when chains between the motor and the drive-shaft failed at a gig in Surrey, the hearing was told.
Mr Grills and Mr McMullen had been preparing for a sold-out gig at G-Live theatre in Guildford on February 9, 2013, and were standing in the venue's loading bay when tragedy struck, a jury heard.
A staff member had suggested opening the door, which was around 12ft tall and 40ft wide according to fellow band member John Cleave, to allow their tour bus to drive inside.
But as it was wound aloft, it suddenly collapsed.
David Naylor, 57, the boss of Express Hi-Fold Doors Ltd which manufactured the door involved, is accused of two counts of manslaughter by gross negligence in connection with the deaths of the two men.
It is the prosecution's case that Mr Naylor is guilty of the very serious crime of gross negligence manslaughter.
Naylor denies two counts of manslaughter by gross negligence .
Express Hi-Fold Doors Ltd denies breaching general duty regarding articles and substances for use at work