There will be times your interaction will be as little as a sentence long because it's all they can feasibly do in a decent timeframe, or that they are acting and then waiting for a reaction, or a retort, or something. This is okay. It blows the whole 'one liners are terrible' out of the goddamn water, because there are occasions where the most your character has to contribute in between is perhaps a line or two. Any more would be fluffy nonsense. :U