HELP ME PLS

Mike got out of the driver seat of the classic car. He looked at the mailbox and then at the bumper. The mailbox was smashed and bent. The shiny chrome bumper had a dent about the size of a football around the passenger side. Mike shook his head and got back in the driver seat. He knew what he had to do. He didn't want to do it, but he had to. He drove back home and sat in the driveway for a few minutes, holding his head in his hands. Mike's dad came out of the house carrying a black garbage bag. He smiled and waved at Mike as he passed the driver side of the car. Then he looked again as he walked past the passenger side of the vehicle. His mouth dropped open and he let go of the garbage bag.

In the text it says, "[Mike] knew what he had to do." What did Mike have to do? Explain how you know this: