ἀλλ᾽ ἄλλοι μενέουσι κάρη κομόωντες Ἀχαιοὶ
εἰς ὅ κέ περ Τροίην διαπέρσομεν. εἰ δὲ καὶ αὐτοὶ
φευγόντων σὺν νηυσὶ φίλην ἐς πατρίδα γαῖαν:
νῶϊ δ᾽ ἐγὼ Σθένελός τε μαχησόμεθ᾽ εἰς ὅ κε τέκμωρ
Ἰλίου εὕρωμεν: σὺν γὰρ θεῷ εἰλήλουθμεν.
This is Iliad 9.45 ff. αὐτοὶ does not mark a subject shift here – it refers back to the subject of the previous sentence, namely, κάρη κομόωντες Ἀχαιοὶ! καὶ αὐτοὶ here is emphatic, and αὐτοὶ is not a simple personal pronoun. There’s an anacoluthon or rather an aposiopesis after εἰ δὲ καὶ αὐτοὶ. “But the other Acheans will stay at least until we sack Troy. But if they too . . . then let them flee with their ships to their homeland.”
οἱ δ’ ἐνέκλιναν καὶ αὐτοί. – The subject shift is marked by οἱ δ’, indicating that the subject of ἐνέκλιναν is not οἱ τῶν Μήδων δ’ ἱππεῖς but rather refers to τοὺς ἱππέας τοὺς τῶν πολεμίων. καὶ αὐτοί does not mark the subject shift – it’s predicative to οἱ δ’!
ἐπειδὴ ὁ λόγος οὕτως αἱρεῖ, μὴ οὐδὲν ἄλλο σκεπτέον ᾖ ἢ ὅπερ νυνδὴ ἐλέγομεν, πότερον δίκαια πράξομεν καὶ χρήματα τελοῦντες τούτοις τοῖς ἐμὲ ἐνθένδε ἐξάξουσιν καὶ χάριτας, καὶ αὐτοὶ ἐξάγοντές τε καὶ ἐξαγόμενοι, ἢ τῇ ἀληθείᾳ ἀδικήσομεν πάντα ταῦτα ποιοῦντες
καὶ αὐτοὶ ἐξάγοντές τε καὶ ἐξαγόμενοι, – there’s no a subject shift here: it’s just a parenthetical afterthought that includes those who are ready to assist the escape with the escapee in the subject of δίκαια πράξομεν. Socrates is concerned for their moral well-being, too:
“. . . there’s nothing else to consider other than . . . whether we will be acting justly in granting favors and paying money to those who are ready to assist my escape from here – those who are ready to assist in the escape just as much as those of us who would be escaping – or whether in truth we will be committing injustice if we do all these things.”
Again, καὶ αὐτοὶ is not a subject shift – it’s emphatic and intensive, and the emphasis that the moral issue applies as much to the persons ready to assist in the escape as to the prospective escapee is intensified by the tight connective τε καὶ. There’s a slight disconnect, in that the assistants in the escape would be receiving, not paying, money and favors.
I’m sorry, but it isn’t helpful to the OP to cite examples that are not pertinent and in fact actually illustrate the opposite point.