A pretty complex device too. I'm not sure about this specific one, but LIDAR tend to operate in a scan fashion with a refresh rate. This means it can get chopped noisy data in a time sense which requires post-processing.
That would not have mattered im this case. The Veldoyne LIDAR they seem to be using (from the photo of one of their Volvos) is the HDL-64E (don't know which revision but the key specs are the same). This sensor can operate between 5 and 15Hz (full rotations per second). So in the slowest setting the car (assuming it was going at 45mph) moves 4 meters within a full rotation and in the fastest setting moves 1.5 meters.
That might sound a lot, and in some applications it is a lot, but please keep in mind that after one full rotation the sensor has scanned an area of up to 45000 square meters ( maximum scanning distance is 120 meters). So each rotation gives you a pretty good situational awareness of your surroundings (barring any occlusions that prevent the sensor from seeing certain spots). Unless the person is covered in IR absorbing material (some black materials do a quite good job at that) it should be impossible for a pedestrian to sneak up on the car without it being sweeped multiple times by the laser beams
