Once Stanley dropped Rachel off in front of her house, he drove back to his house. After that, he let Stephen take over the wheel.
Before getting out of the car, he made sure to inform Yvonne that she could take the front passenger seat. Yvonne just claimed that it was too troublesome for her to shift seats, so she curled up on the backseat without the intention to move.
Stanley sensed that something was off, which prompted him to shoot glances at Stephen and Yvonne. At the same time, he wonde