It's referencing the myth of the birth of Huitzilopochtli, the god of war and patron of the Mexica -- Coyolxauhqui was his sister, and, short version of a long story, tried to murder her mother and brother before he could be born, fearing he would be more powerful than her. Unluckily for her, she was a bit too late and he was like Athena, born full-grown, and proceeded to kick the everloving shit out of her. The stone shows the end of the myth, where she lies in the dust, torn to pieces, after having been flung down from the sacred mountain of Coatepec. It's a story with both cosmic significance (Huitzilopochtli also represented the sun, while Coyolxauhqui was linked to the moon, and her army was the stars (who were also often death spirits, standing by to unmake the world at the end of an age)), as well as political -- Huitzilopochtli was the specific patron of the Aztec/Mexica people, and his destruction of the old war goddess and ascension to power was symbolic of the rise of the city-state of Tenochtitlan and the Aztec Empire. All who opposed them would end up like the defeated goddess -- torn to shreds on the battlefield and cast down from the sacred mountain/Grand Temple.) I actually like the tattoo, but it's an odd choice for a Baptist minister.
The tats on her left wrist and chest are also Aztec. Can't see the wrist one well enough to tell if its the atl-tlachinolli ("burning water", the glyph for "war") or a bracelet of smoking mirrors (these have a ton of meanings, but one of the main ones is a magic mirror with the divine power to unveil knowledge, many of the gods are shown carrying, wearing, or using them). The one on her chest I believe is from a codex (the Aztecs had pictographic books), but I can't be 100% sure which scene it is without being able to see the whole thing, and well... given where it is, I'm glad I can't. <shudder>
