My response is that talking is a free action, but deciding what to say is not. I'll pause the action to let you shout out orders or threats or monologues, but you cannot converse during a single round (except in the dead time while somebody else is attacking).
Also, there was a great rule in Conquistador in the seventies, which forbade movement "in contravention of common sense". If somebody attempted the peasant railgun in my game, I would say, "Get serious", and move on.