The best possible time is about 50 seconds, i will do better calculations tommorrow, but it should be about 50 seconds if you get incredibly lucky with the zombies

Looks like I've got about 8 more seconds to clean up then

i did the calculations:

1% takes 500ms to pass you now need to add the time of getting to the car at the start which takes about 867ms that equals to 50seconds 867milliseconds (0:50.867) (only reacheble if you get incredibly lucky)

Alright, makes sense. But you have to, at least once, address the zombies at the doors (or 1 if you get 2 of them at 1 door) and that takes away roughly 6-7secs (depending on your shot)... so, how can we make it where you don't have to kill a zombie? That is the only way I can see the time being at that 50sec mark.