In the level Proving Grounds, you have to follow a Little Sister as she opens doors for you.
Mine just got killed near the end, Tenenbaum told me I could get a new one, but also state that one lost is already too much.
I systematically saved every Little Sister instead of harvesting them until now. Could I get a new one without any impact on the end or should I load my save-game and try to escort her safely? What if she got killed again?