James Swallow wrote:
And while Lwaxana does get a namecheck, anyone who thinks the title is to do with her or the Sacred Chalice is off-base. This is more about the Macbeth
Said quote being Act I Sc. vii
l. 10-12: "This even-handed justice / Commends the ingredients of our poison’d chalice / To our own lips." Macbeth is hesitating over the killing of Duncan because he's contemplating the consequences that will befall him if his crime is discovered.