After quoting the Mūlamadhyamakakārika 24:18 verse, Chih-i continues:

The characteristics of those in the six destinies [from hell to divine] corresponds to “all things which arise through conditioned co-arising.” The characteristics of those in the two vehicles [śrāvaka and pratyekabuddha] and the bodhisattva of the Shared Teaching corresponds to “I explain as emptiness.” The characteristics of the bodhisattva of the Six Pāramitās [Tripiṭaka] and Distinct Teachings correspond to “Again, it is a conventional designation.” The characteristics of the Buddha-realm corresponds to “Again, it is the meaning of the Middle Path.”
[T 46, 695c15-18]

In other words, those in the six lower destinies perceive the world in its arising and perishing as the interplay of interdependent causes and conditions. Śrāvakas and pratyekabuddhas perceive the world as empty of substantial Being and thus to be characterized as neither arising nor perishing. The bodhisattvas go a step further and perceive the immeasurable conditioned phenomena of this world as provisionally existent, albeit having existence merely as conventional designation. The Buddha, in his perfect wisdom, spontaneously perceives the world as it truly is – uncreated, beyond description, beyond conceptual discrimination, subtle, the Middle Path.

This is where Chih-i reaches his ultimate conclusions. In the final analysis, all of reality is an integrated, interdependent unity. Everything contains everything else, and the whole contains all things.

In the [ Profound Meaning of the Lotus Sutra] this is described in terms of “the interinclusiveness of the ten realms” or “the interpenetrating unity of all aspects of reality”. As Chih-i puts it:

One dharma realm contains ten suchlike characteristics. The ten dharma realms thus contain one hundred suchlike characteristics. Also, each dharma realm contains the other nine dharma realms, so there are one hundred dharma realms and one thousand suchlike characteristics.

The actual number, whether a thousand or a hundred or whatever, is irrelevant; what matters is the inclusion and interpenetration of all of things in one reality.