Krishna describes the inner awareness of one who knows the truth. Seeing, hearing, touching, smelling, eating, walking, sleeping, breathing — all of this keeps happening. Yet the knower holds a firm conviction: 'I am not the doer.'
Consider a river. Water flows, stones come in the way, banks shift. The river does not 'do' any of this — it simply moves according to nature's laws. The yogi understands in the same way: these actions belong to the senses and their objects. The 'I' is not involved.