How does the felony-murder special circumstance apply to a person other than the actual killer?

circumstance applies to "a person other than the actual killer . . . if that person was a major participant in the underlying felony . . . and either intended to kill or acted with reckless indifference to human life." (People v. Cleveland (2004) 32 Cal.4th 704, 752, italics added.) Neither of those mental states is required for the actual killer. (People v. Contreras (2013) 58 Cal.4th 123, 163-164 ["[t]he felony-murder special circumstance . . . is valid absent any requirement that a defendant who actually killed during an enumerated felony acted with the intent to kill"; also disagreeing with the contention that "to withstand constitutional scrutiny, the felony-murder special circumstance . . . minimally requires a finding of 'reckless indifference to human life' for actual killers lacking an intent to kill."].)