The only way that entrainment can cause damage to your ears is when you play it WAAAAAY too loud.
It should be played at a comfortable level, or even below that.
Brain entrainment is nothing more than a slight difference in frequency
Frequency means height of tones. The higher the tone, the higher the frequency of soundwaves.
If this would cause tinnitus, everybody would get it from daily life allready.
If for instance an ambulance comes rushing by, the sound is compressed by the speed of the ambulance relative to your ears. As soon as it passes, the sound seems to be lower, because now the soundwaves are stretched ( Doppler effect )
So, if the ambulance passes you by from left to right, there allready is a slight difference between the left and right ear in frequency as the ambulance rushes by. This is not harmful to the ear in any way.
It's not frequency that can cause harm, it's volume. If the volume is too high, the hair cells (stereocilia) in the cochlea ( the part of your inner ear that is responsible for hearing ) move so violently, that they are permanently damaged. This will result in loss of hearing, and this is permanent. The problem with tinnitus is that these hair cells are damaged, and thus constantly tell the brain that they hear a sound. Usually this is like a ringing kind of sound, which is what tinnitus means in latin.
This is not the only cause of tinnitus, but it is the most common.
In my opinion, playing it too loud is the only way to get tinnitus from LifeFlow.
Hope it helps !