Snapping is a term in Mistborn, meaning a person’s magic ability being awakened when encountering some life-death situations.
My mother is not a Misting, as Allomancy does not exist on the planet Earth, but we have archangels.
When my mother was trying to get up after being pushed by my father toward the edge of the staircase, she accidentally hit my father’s ankle. All of a sudden, Archangel Michael channelled his power through her, and my father’s ankle was broken, disabling his ability to walk for a month.
Few years later, my father was trying to push my mother to the ground again in the heat of an argument. To prevent herself from falling, she grabbed his arm, and then Archangel Michael struck again, paralyzing his arm. When they went to a bonesetting house, the shifu stared at my father’s broken arm and said “Even God can’t save this!” at first sight.
Now when she’s facing a potentially violent argument, she will start channeling and filling herself with the power of Archangel Michael to protect herself and give her confidence.
(Based on my mother’s perspective)