I like the thugs in the hallway waiting to jack you up idea.
How many deaths would it take the player to even figure out that the door is not the way out?
lol
Then you need the duct high so they have to move boxes or something to reach it.
More encouragment to use the obvious, the door.
PS @ Nickydude
Please edit the scancodekeypressed explination in your guide.
It says the TAB key is #5 but it is #15. (I noticed it the other day and forgot to mention it)
Your image was fuzzy and made the 15 look like a 5, so honest mistake, but it still needs to be corrected.
That is if you haven't fixed it already. (I may have an older copy)
Another thing to add to the guide would be the action to adjust the headshot height.
I know Lee added this shortly after giving us the headshot=x action, but I can't find info on the action or the thread.