Parallel
Acts 12:9
Patriarchal Greek New Testament (1904) · Berean Standard Bible
καὶ ἐξελθὼν ἠκολούθει αὐτῷ, καὶ οὐκ ᾔδει ὅτι ἀληθές ἐστι τὸ γινόμενον διὰ τοῦ ἀγγέλου, ἐδόκει δὲ ὅραμα βλέπειν.
So Peter followed him out, but he was unaware that what the angel was doing was real. He thought he was only seeing a vision.