Kṛṣṇa describes the ‘lockdown’ phase of internal yoga. To establish oneself in ‘yoga-dhāraṇām’, one must close all the ‘gates’ of the senses (eyes, ears, etc.) to prevent external data from entering. The mind is then confined within the heart, rather than being allowed to wander into material memories. The practitioner then pushes their life air (‘prāṇa’) to the very top of the head. This is the process of ‘sensory withdrawal’ and ‘internalization’. The yogī is effectively shutting down the body’s connection to the outside world to focus all energy on the spiritual exit point. This describes a state of total concentration. It is the physical and mental equivalent of preparing for a launch. Kṛṣṇa is showing that reaching the Supreme requires a deliberate withdrawal of interest from the temporary world. It is a total mobilization of the self toward the one point that matters.