I just saved my 3rd little sister in Bioshock, and the female doctor (I forget her name) said something along the lines of "I'm still not sure if you're friendly to us, but this Little Sister is going to give you something for helping us".
A message box then flashed up on the screen, but I happened to be shooting someone else at the time, and it closed before I even had a chance to read it.
What did it say?