towards its blades- their blades (the subject is the 'choppers', isn't it?)
soldiers propelled down - climbed/abseiled?
liberating the locals of - from
Dust densed the air - unusual usage
With their guns, slinged at their shoulders- no comma and I'd say 'slung'
Edmund was reminded by his platoon head's words- reminded of
gulping down rapids of water- I'm not too keen on the use of 'rapids' here
He was save- safe