Sgt Stephen Sands put his hands up when confronted by a man pointing a sawn off shotgun at his chest.
Then he heard a second man shout, 'Come on - waste him', at least twice.
Danville Gibson, 23, of Balham, south London, denies soliciting the murder of PC Thompson and Sgt Sands and attempting to murder another police officer, PC David Feaster, on 23 November last year. He also denies firearms offences.
The trial was adjourned until today.Reuse content