I don’t think she’s actually dead, she just faked her death to go do research to fix the problem of clones having shortened lifespans. BTW this isn’t a problem anymore, we figured out how to regrow the telomeres in somatic cells so that clones have normal life expectancies already IRL.
This whole thing is kind of convoluted, it’s not like she would kill everyone on a plane to do this. Then again all the other passengers may be in on it. A woman at the airport said her husband who was a doctor was on the plane and a man said his daughter who was a PHD student was on the plane too. They were supposedly doing a medical mission, that’s a good enough excuse to get a bunch of scientists on a plane together.