The even-mindedness of a fully awakened person is an attitude not of cold indifference, but rather of mental imperturbability.
"[An awakened person] feels sympathy for others and seeks their well-being, experiencing a sense of satisfaction when they respond to [his/her] teachings, but otherwise [he/she] stays equanimous, untroubled, mindful, and alert. This passage shows that the even-mindedness of a fully awakened person is an attitude not of cold indifference, but rather of mental imperturbability. Such a person has found true happiness and would like others to share that happiness as well, but that happiness is not dependent on how others respond. This is the ideal state of mind for a person who truly works for the benefit of the world." ~ Thanissaro Bhikkhu "The Wings to Awakening"