When it comes to finding synonyms for the phrase "one at control," there are a few options available. You could use "in charge," "managing," or "overseeing" as alternative terms. These phrases imply that the individual is responsible for guiding the operation and ensuring that everything runs smoothly. Another option is "at the helm," which is a nautical term that indicates the person is at the wheel or steering the ship. Similarly, "in command" can be used to describe someone who is leading and directing a team or group. Ultimately, the right synonym will depend on the context and tone of the situation.