The biggest slaughterhouse in the capital was near the farmers' market. Leng Pan and her companions had to drive almost across half of the city to get there. It took them only thirty minutes to get there because there was no traffic on the road.
Even the few cars they came across of survivors who were starting to go out and explore the post-apocalyptic world couldn't count as traffic.
Hence, apart from zombies running after their car, there weren't any obstacles. Instead of locking the truck window and just running over the zombies or watching them chase the vehicle in vain, Leng Pan opened it and began to attack them.
She used her temperature-controlling ability to turn her water superpower into snowflakes shaped like ninja weapons and hurled them at the zombies. Some decapitated the zombies while others sliced off their limbs.
Traveling like this for half an hour, they arrived at their destination and found the place surrounded by zombies.