My character would be saying ef that because that would just make us vulnerable. If we were on top of a bus. He would tell them how it is a bad idea and stuff. If the characters can get the bus started then maybe they could get out of town. Although the book says that during the first few hours of the outbreak that it is a bad idea to try and drive out. It will make more traffic that is already there. We in essence would be a giant tube of food for the undead. Maybe if things weren't going to fast he could think for a second and be like... hey lets go to my house. Stick it out for a few hours and what not. That and he lives on the second floor. The stairs are wooden allowing quick whop chop action to getting the only way out or in out of the way. 

In outbreak level 3 there are so many zombies around that they will pile up on one another to get over most obstacles. Assuming the outbreak is just starting then the amount of zombies are scarce. There are a few here and there. Putting too many people into the mix usually leads to panic and dumb people doing stuff. Like crushing people below them. Widespread panic seems unimaginable although people are in essence dumb and give into the fight or flight. Either they gain courage and fight via military background or whatever… or they run. Most everyone will run because in essence most people are cowards.