[huylibizonoff]

A friend of mine says that samatha is like putting the key into the lock and vippassana is like turning it.

Vipassana does not require any turning

Does watching a leaf fall from a tree or the waves lapping upon the sea shore require any "turning"?

Impermanence is the whole world turning. The whole world is both within & without. "Turning" the mind cannot help see the "turning".

The mind must stop its "turning" be able to see clearly the turning.

"Turning" = samsara

A mind in samsara cannot see samsara because a mind in samsara is drowning in the samsara

All the best