Business partners Will Henry, 31, and Brian McIntosh, 29, were shot dead in the vehicle at Albion Works in Brierley Hill last September.
Skip company boss Jonathan Houseman, 33, from Stourbridge, is accused of shooting the pair over a £200,000 debt he owed them.
Richard Avery, also 33, is alleged to have help plan the killings.
Both denied murder and went on trial at Birmingham Crown Court.
Jurors retired at around 1pm on Wednesday.