Again it's always interesting to remind how dangerous these devices might be due to their reflecting nature, as well the beam itself under certain thresholds of power.
When you direct a laser to some point, multiple surfaces reflect parts of the beam. The eye doesn't see that light or with other words the brain doesn't receive information. Nevertheless there's a high chance for energy coming other time to your eye causing damage.
This principle is severely utilized in speed or distance measurements with lasers. Emitting rays and waiting for the reflected ones, now, a time variable appears, and as obviously the laser speed within the medium is known, a few calculations and you will have verifiable data. Those devices almost always work, so it's then clear how the rays are constantly reflected from multiple points.
Working with lasers it's always recommended wearing eye protection if the laser has enough power to be worrying. Specifications sometimes aren't real or can vary. With doubts, protection and in controlled environments without unprotected people.