TIPS: This is not exactly a bug but in case you are playing the game on Hardcore difficulty, the starting section of the stage, where Issac enters the transport hub and has to wait in Vacuum till Ellie opens the CEC doors, this can be cleared without spending any ammo or taking any damage at all. Before entering make sure you have at least 70% health, as soon as you enter hurry and collect any items as soon as you see the first necromorph, start running in the widest circle possible around the entire area staying close to the walls, this way the necromorphs will keep following but never catch up to you. Make sure you run in the widest circle possible in that area till Ellie opens the CEC doors.