The rover abrades rocks using a tool on its robotic arm before drilling them in order to clear away dust and weathering rinds, allowing other instruments to study the rocks and determine if scientists want to grab a sample of them. In this case after studying this patch the team decided not to take a sample at this stage, and have just driven away from the location. This could be because they have a limited supply of empty sample tubes, and they want to check the region thoroughly before deciding which targets to obtain a rock core for sample return.