噼

Left-side mouth radical - pictograph of an open mouth, the small square shape. The indexing radical, and pure semantic fit: 噼 is an onomatopoeic verb (噼啪 'crackle, snap, pop'), the sharp cracking sound of firecrackers, breaking branches, or rapid slaps. Most 口-radical chars exist solely as sound-imitations: 嗡 buzz, 呜 howl, 嘟 toot, 啪 clap.

Right side 辟 supplies the sound: pì to pī with tone shift only. 辟 itself depicts a kneeling figure punished by a knife - originally 'to rule by law,' surviving in 开辟 open new ground, 复辟 restoration. As phonetic 辟 also gives 譬 metaphor, 僻 secluded, 避 avoid, 劈 cleave - 劈 reinforces the crisp 'split' sound mirrored in 噼.