μηδ᾽ ἀφεστάναι φρενῶν: Eur. Or. 1021“ἐξέστην φρενῶν”. For “ἀφεστάναι”, cp. Vesp. 1457 “τὸ γὰρ ἀποστῆναι χαλεπὸν” | “φύσεος”. The words convey a hurried reproof and warning,—‘do not lose your wits’ (through fear). All their presence of mind is needed, since Philoctetes is awaking.