Some shouting one thing, some another (alloi allo tōi epephōnoun). Same idiom of alloi allo as in Act 19:32 which see. The imperfect of epiphōneō, to call out to, suits well the idiom. This old verb occurs in the N.T. only in Luke and Acts (already in Act 12:22).
When he could not know (mē dunamenou autou gnōnai). Genitive absolute of present middle participle of dunamai with negative mē and second aorist active infinitive of ginōskō.
The certainty (to asphales). Neuter articular adjective from a privative and sphallō, to make totter or fall. Old word, in the N.T. only in Act 21:34; Act 22:30; Act 25:26; Phi 3:1; Heb 6:19.
Into the castle (eis tēn parembolēn). Koinéš word from paremballō, to cast in by the side of, to assign soldiers a place, to encamp (see note on Luk 19:43). So parembolē comes to mean an interpolation, then an army drawn up (Heb 11:34), but mainly an encampment (Heb 13:11, Heb 13:13), frequent in Polybius and lxx. So here barracks of the Roman soldiers in the tower of Antonia as in Act 21:37; Act 21:22 : Act 21:24; Act 23:10, Act 23:16, Act 23:32.