Damn. The Fourth Survivor is rough. Made it to the West Hall and got murdered. Seems like there is a lot of luck involved in evading zombies and dogs.
With dogs, there is very little luck; they follow fairly set initial paths, and by the time the variation comes in, you should be long gone.
Zombies... The only luck comes in whether or not the ones you need to stun will get stunned with the first bullet. Some of the timing for the tighter areas requires you to shoot a shot and keep running. If the zombie decides to not flinch, then yeah, it can go South.
But by and large, 4th Survivor is a fixed puzzle that relies very little on luck.