Stopped in their tracks meaning

Also, stop dead or in one's tracks or on a dime. Halt suddenly, come to a standstill, as in When a thread breaks, the machine just stops cold, or He was so surprised to see them in the audience that he stopped dead in the middle of his speech, or The deer saw the hunter and stopped in its tracks, or An excellent skateboarder, she could stop on a dime. The first term uses cold in the sense suddenly and completely, a usage dating from the late 1800s. The first variant was first recorded in 1789 and probably was derived from the slightly older, and still current, come to a dead stop, with the same meaning. The second variant uses in one's tracks in the sense of on the spot or where one is at the moment; it was first recorded in 1824. The third variant alludes to the dime or ten-cent piece, the smallest-size coin.