Pratyahara or withdrawal of the senses is a practice of turning our attention inwards, so that we observe how the senses react. We retreat to our inner world, not to escape the external world, and most certainly not to be blind to the suffering of others, but to find the inner peace that is independent of the external world. In the beginning, we may thread only at the superficial level of the mind. But with practice, we eventually tap into the knowledge of the Self that is beyond the glass ceiling of the mind. When we know how to do this, we can then go back to the external world and become more active, because we are not slaves to our senses and we instead operate from a better understanding of the Self.
We can live our lives chasing after sensations we like and running away from sensations we don't like. This is the easier path, but it is also a path that keeps us trapped in a never-ending loop. As yogis, we can take another option, the more difficult option in which we become masters of our senses. It requires practice and discipline to learn how to go inwards, but ultimately this is what could lead us to absolute freedom and liberation.