What is this form ἀνασχεθεῖν? My guess is that is an infinitive with πρίν. Does it just collocate with the torches, or eith all the things she has done for them?
ὦ τέκνα τέκνα, σφῷν μὲν ἔστι δὴ πόλις
καὶ δῶμ᾽, ἐν ᾧ λιπόντες ἀθλίαν ἐμὲ
οἰκήσετ᾽ αἰεὶ μητρὸς ἐστερημένοι:
ἐγὼ δ᾽ ἐς ἄλλην γαῖαν εἶμι δὴ φυγάς,
πρὶν σφῷν ὀνάσθαι κἀπιδεῖν εὐδαίμονας, 1025
πρὶν λουτρὰ καὶ γυναῖκα καὶ γαμηλίους
εὐνὰς ἀγῆλαι λαμπάδας τ᾽ ἀνασχεθεῖν.
Poetic aorist infinitive from ἀνέχω. Yes, it’s taken with πρίν. I would read it just of the torches.
Thanks, Barry, and sorry in advance for (these following few questions) what I’m about to ask about and complicate with … 
Are there any lines of reasoning that lead us prefer dative over genitive or genitive over dative in our grammatical understanding for the σφῷν here?
Considering that ἐπιδεῖν, ἀγῆλαι and ἀνασχεθεῖν all have Medea herself as the subject, is σφῷν necessarily genitive here because this ὀνάσθαι too is Medea talking of herself in the middle as their mother or could it be a dative of respect with an impersonal use of ὀνάσθαι?
2. σφῷν - form
This particular form being a contraction of σφῶϊν is straightforward enough, but is there a reason why the omega is in the form that the dual ending ιν is added to? Is that omega part if the dual morphology, or part of the base form of the pronoun itself?
3. λουτρὰ - meaning
Is this λουτρὰ part of a set with the other wedding words and alluding to a ritual or customary washing as part of the lead up to the wedding ceremony, or is it a reference to her general care during childhood? My guess is that if it was a word of general care, it would be in the previous πρὶν clause.