I think the way to look at it is beta is Se-valuing+Fe, and to note that Fe, in Gulenko notation is E, i.e. emotion, i.e. the component of feeling-judgment which moves you through arousal (the dynamic variety). This Fe along with Se means a seeking out of that arousal, in tandem with the "moving" aims of Se, i.e. to influence objects (involved) rather than simply note their potential.

Si is an introverted form of consciousness, overall more about the passive, less involved, subjective impressions of sensory experience, and by the way, in some versions Si is sensitive to emotive content, simply that it is not responsible for the production of human sentiment (that is a hallmark of a rational creature), well-defined attitudes towards things...but it is responsible for reactions to things.
This creates more of a tendency to note if the surroundings agree with one's constitution on an instinctual level than contributing to the formation of anything like a developed ethical agenda.

Negatively signed Fe + Si might be seen as emphasizing that tailoring the arousal of objects to their constitutions, so as not to aim to change their kinetic energy so much as keep them involved in the overall grand scheme of energy exchanges -- honor their constitutions and their relative position within the said scheme/sphere.