For checking the transcript: https://www.buzzsprout.com/2379282
In the driver's sit
means being in control of a situation or having authority. It’s like being the driver of a car, where you decide where to go and how to get there.

Examples:
1- After months of hard work, John finally got his startup off the ground and was now in the driver's seat, calling the shots.
2- Ever since I bought a new gaming console, my younger brother has been in the driver's seat of our living room, controlling the TV remote and the game time!