The lights are on
it easy to get all completes for no mercy, dead air , etc just play through at the last level right when ur ride shows up make sure their are no infected near you then pause the game vote to change diffculty change it to expert as soon as it changes to expert get on the escape vehicle. It should work but it doesnt always work but when it does you should get an achievement for completing it and get 1 of 4 what you trying to prove achievement.
Wow...are all of the posts going to be like this? Incorrect punctuation or grammar; Should work doesn't always work but when it does you should get...This isn't a guide either, it's a work aorund or cheat flaw. Anyway, my two cents.