... set out in an army vehicle. (Para. 3)
Meaning: ... started the journey by riding in an army vehicle
set out: start a journey.
This phrase can be replaced by "set forth" or "set off".
They set off in search of the lost child. 他们出发去寻找失踪的小孩。
n. 短语,习语,个人风格,乐句
vt. 措词