This is my save from the very last mission, last target [Haverlock]. All you have to do is shoot Haverlock with the sleep dart, ignore the ones sitting at the table since they are already dead [scripted that way, I didnt kill them]. Once that target is knocked out, grab the key from the table beside them, open the locked door and release Emily.
Doing these VERY SIMPLE steps will unlock the following SIX achievements:
"Long Live The Empress" - 10 gamerscore
"Resolution" - 100 gamerscore
"Clean Hands" - 100 gamerscore
"Ghost" - 30 gamerscore
"Shadow" - 30 gamerscore
"Just Dark Enough" - 50 gamerscore
a very easy 320 gamerscore, including 3 hard to get achievements.