Sir Richard C. Jebb, Commentary on Sophocles: Ajax

εὐθὺς ἐξ ἕδρας, immediately on rising from his seat beside Calchas (750 n.). No sooner had Calchas finished, than Teucer rose, and sent the messenger, who was close by,—sitting among the “λαοί”. (Cp. Il. 2. 96“λαῶν ἱζόντων”,—in the agora.) Some take “εὐθὺς ἐξ ἕδρας” as= ‘immediately, from his seat,’—i.e., without rising (so that he would beckon or call the man to him): cp. Il. 19. 77“αὐτόθεν ἐξ ἕδρης, οὐδ᾽ ἐν μέσσοισιν ἀναστάς”: Od. 13. 56（“ἔσπεισαν”) “αὐτόθεν ἐξ ἑδρέων”, ‘even there as they sat.’ But in those phrases “αὐτόθεν” helps to fix the sense: whereas “ἐκ” following εὐθὺς regularly denotes the point from which the further action sets out (“εὐθὺς ἐξ ἀρχῆς, εὐθὺς ἐκ νέου”, etc.). Hence “εὐθὺς ἐξ ἕδρας” ought to mean, ‘immediately after sitting.’— Other explanations of “ἐξ ἕδρας” are: (1) ‘from where I (the messenger) sat.’ (2) ‘After the sitting of the council.’ But Teucer would not wait for that. (3) ‘Leaving the council’ (or strictly, its neighbourhood, since Calchas had come apart from it, Od. 750). This would imply that Teucer had been included in the “ξύνεδρος κύκλος”: but the tone used towards him by Menelaüs (1120 “ὁ τοξότης”) and Agamemnon (1235 “δούλων”) makes this very unlikely.

Teucer sends a messenger, instead of going himself, probably because he hopes that his mediation with the chiefs may do some good. What he dreads is simply that Ajax should leave the tent; and a message could prevent that. He has no cause to suspect that Ajax meditates suicide.