That is all.External link →
As soon as the mission starts and just as you're about to exit the drop pod is when V should be first pressed in a mission. It's the signal to charge.
Funny story. It used to be “Rock and Roll”, but one of the dwarves tripped and rolled down the ramt after yelling that, so now - as a safety precaution - it’s “Rock and Stone”. notactuallore