What is the test for a person to be found guilty of manslaughter for killing in imperfect defense of others?

[O]ne who kills in imperfect defense of othersin the actual but unreasonable belief he must defend another from imminent danger of death or great bodily injuryis guilty only of manslaughter. (People v. Randle (2005) 35 Cal.4th 987, 997, 28 Cal.Rptr.3d 725, 111 P.3d 987 (Randle ) [recognizing imperfect defense of others].) To satisfy the imminence requirement, [f]ear of future harmno matter how great the fear and no matter how great the likelihood of the harmwill not suffice. The defendant's fear must be of imminent danger to life or great bodily injury. [T]he peril must appear to the defendant as immediate and present and not prospective or even in the near future. An imminent peril is one that, from appearances, must be instantly dealt with. ... Put simply, the trier of fact must find an actual fear of an imminent harm.

[61 Cal.4th 271]