Mitzvot as a means of life

Hello Rabbi,
In your book ‘Walking Among the Standing’, in the chapter on Halacha and Morality, you bring up the dispute between Samuel and Rabbi Shimon ben Menasya in the conflict between Pikuach Nefesh and Shabbat observance.

Initially, you pose the dispute as whether life is a means to the commandments or whether the commandments are a means to life.
Ultimately, you write that according to Rabbi Shimon, it can also be explained that he believes that the mitzvot are a means to life (and the dispute is about a different question).
I don’t understand this explanation. It’s clear that a secular person who lives and doesn’t observe the mitzvot is not ‘in order.’ Beyond that, you also write several times that mitzvot are religious values, meaning goals and not means.
Can you expand and reconcile these things? What does it mean that the commandments are a means to life?
thanks,
given