A.T. Robertson Commentary Luke 22:47

"While he yet spake, behold, a multitude, and he that was called Judas, one of the twelve, went before them; and he drew near unto Jesus to kiss him." — Luke 22:47 (ASV)

Went before them (προηρχετο). Imperfect middle. Judas was leading the band for he knew the place well (John 18:2).