Let me explain.
The guy is on a 90 second timer, right?
When he enters the vehicle, I want that timer to be stopped.
That's what I want.
There are so many things wrong with your code, it's better to start from scratch. It makes no sense.
onVehicleExit and onPlayerSpawn are not functions, they are events (actually they are functions, but inside classes and it's not good to depend on them)
First, you'll have to found the proper function for exiting a vehicle and when the player spawns.