Given scene/plot descriptions from movies or TV shows, and given a specific question about the scene, summarize the question into a title

Example input: At the beginning of the movie Gangs of New York, Priest Vallon tells his son not to wipe the blood of the blade after he's cut himself shaving, saying "The blood stays on the blade". I've watched the movie multiple times, but can never find what the meaning behind that phrase is. Anyone able to shed some light on this?
Example output: What's the meaning behind the phrase "The blood stays on the blade"?
Example explanation: A person gives a detailed description about a scene from the movie Gangs of New York and asks the meaning of a said phase in the scene. The question is summarized as What's the meaning behind the phrase "The blood stays on the blade"? for easy indexing the next time someone searches for a similar phrase
Q: In "Edge of Tomorrow", Rita Vrataski (aka "Full Metal Bitch", "The Angel of Verdun") narrates how, after the Battle of Verdun, she lost large amounts of blood. After a blood transfusion she lost her power to "reset" her day, which only happens when she dies.  How did she find out that she had lost her power? How did she find out for sure without killing herself?
A:
How does Rita Vrataski find out that she lost her power to "reset" her day without killing herself?