The faculties of eye, ear, nose, tongue and the body have different scopes and ranges. It means that for example, eye cannot do what ear can do and nose cannot do what tongue can do etc.
They recourse to mind means that they cannot process sensory data on their own and the processing is done by mind for all six senses which includes the mind. For example, eye consciousness arises depending on the eye and the form but the mind has to pick it up from there. This is why the mind is called the forerunner and the chief.
Mindfulness is like a watchman for the mind of a practising disciple of the Buddha. That is to say that the watchman of mindfulness ensures that mind does not stray off course.
This way, the disciple understands the true nature of mind which is its impermance. Whatever is impermanent is suffering and whatever is impermanent and suffering is not self. When the disciple understands these three characteristics of all phenomena of which mind is one, the disciple reaches freedom by not grasping anything because grasping , in brief, is suffering.
Freedom and Nibbana is the same.
This is how I understand it and hope it is helpful to you.
Body (sense organs) → Mind → Dhamma/Mind qualities
Just like in Satipatthana sutta. Mind qualities/dhamma (like 5 hindrances) depend on having mind moods (citta) which depends on having feelings which depends on having a body (sense organs).
Liberation is possible because it also depends on these 4 frames. Liberation is a result of the cessation of the 5 hindrances and the arising of 7 factors of awakening, so mind qualities (dhammas) can be ceased and arisen.
The purpose of this is to understand the order and dependency of things (aka idappaccayatā) which is necessary for yoniso manasikara which is necessary for right view and removing defilements. i.e. the only reason liberation is possible is because you have a mind moods/states. Mind moods/states is possible because you have feelings. Feelings are only possible because you have a body (6 sense organs). So the body comes first, and always keeping the body in mind and not forgetting it, aka mindfulness, allows one to maintain a perception of no-self. Attavada happens because people forget that there is a body that must come first, and instead they put “a self which experiences things” first.