Where is the ring in corporate climber?

Climb all the way up, die, do not enter hell but climb the tower once again (hard mode on - with Spiders), on F2 floor (secretary) kill a briefcase worker using a falling lamp bulb and get the briefcase, on F5 floor (angry mailman) auto drop the case in the package tunnel and it will turn into a ring back on F4 floor (running mail carts), go all the way to the top and return again to F4 floor to get it, IF YOU DIE NOW YOU LOSE THE RING and need to do all over again, pass the F4 and F5 levels with the ring in your back and give it to the couple workers at break time level to see the hardests secret.