The zombies won't have a chance if you're armed with these passwords.

Level 2 - EDK-NAI-ZOL-LDL
Level 3 - IDO-GEN-IAL-LDL
Level 4 - ADE-XOE-ZOL-OME
Level 5 - EFH-VEI-RAG-ORD
Level 6 - ADE-NAI-WRA-LKA
Level 7 - EFH-XOE-IAL-LDL
Level 8 - EDK-VEI-IAL-LDL