Alternatively: The plan failed so Alice ends up having to sacrifice herself anyway.
Or Alice was close to death—and sorry, no medical attention for miles.
Parodied: The Smart Guy comes up with a valid strategy that doesn't involve anyone dying. Alice rejects it anyway because she says that someone always has to die in big battles.
Zig Zagged: Alice plans to sacrifice herself, but the group comes up with another way. However, the plan fails so Alice ends up having to sacrifice herself anyway. But at the last minute, The Cavalry shows up and fights off Emperor Evulz, sparing Alice.
Averted: No one sacrifices themselves.
Enforced: "We need to show that The Hero will go all out. Let's have her off herself!"
Lampshaded: "I may be dying, but I die so that millions will live!"
Invoked: Alice learns an attack that costs her life.
Alice refuses to utilize an attack that costs her life, because she wants to live to see the future.
Alternatively, Alice doesn't sacrifice herself because she knows her friends need her, and doesn't want to abandon them like that.
Discussed: "She's...she's really gonna do it? Alice!"