Bioshock 2 Semi Good Ending
One of four endings to Bioshock 2. Sofia Lamb's bombs detonate and cause a section of Rapture to plummet towards a trench. This wounds Subject Delta mortally but he manages to cling to the scape pod. Eleanor kills her mother by preventing her from breathing.
You decide to sacrifice yourself once on the surface. This prevents Eleanor from absorbing your consciousness (memories, conscience etc.) when she tries to extract your ADAM, so she doesn't turn into a horrible person.
To obtain this ending you should harvest and save at least one Little Sister. Choose the Sacrifice Self option when prompted. Sofia Lamb's fate changes if you spare all the characters. If you kill one then she will die.