Three sentences, three moves. The passage consists of a statement, a prescription and a challenge, and each rests on the one before. EXERCISEὈλίγον ἐστὶ τὸ ὑπολειπόμενον — "little of this is left": a demonstrative τοῦτο with no noun, as though there were no longer any need to name life outright. From the brevity what follows is not haste but freedom: there is almost nothing left to lose.
The mountain and the city. ζῆσον ὡς ἐν ὄρει — "live as on a mountain," that is, as a recluse, outside the court and its surveillance. But the qualification at once removes the literalism: οὐδὲν γὰρ διαφέρει ἐκεῖ ἢ ὧδε — "it makes no difference, there or here," DOGMAἐάν τις πανταχοῦ ὡς ἐν πόλει τῷ κόσμῳ, "if a man is everywhere as in a city, in the cosmos." The mountain is not a place but a mode of presence; and it is compatible with a palace precisely because the real polis is the cosmos (cf. 4.4).
Let them look, let them examine. ἰδέτωσαν, ἱστορησάτωσαν — two third-person imperatives: "let them see, let them investigate." The second verb is ἱστορέω, "to inquire into, examine," the same as at 9.37 on observing for a hundred years or three. Marcus offers himself not as a spectacle but as a subject of examination: here is a man DOGMAliving according to TERMnature — check it.
Let them kill him. The close is the harshest in the book: εἰ μὴ φέρουσιν, ἀποκτεινάτωσαν· κρεῖττον γὰρ ἢ οὕτως ζῆν. The ambiguity of οὕτως is deliberate and untranslatable in one word: "to live so" — either as they live, or so as to please them. This is no appetite for martyrdom: death is not chosen, it is merely declared the lesser evil beside a betrayal of one's own way of living. Cf. 5.29 ("the smoke — and I am gone") and 10.8, where the same ladder of outcomes ends in a departure "simply, freely and with self-respect." The governing discipline is action, the sustaining one desire.