Michael Schneider Variety Editor at Large SPOILER ALERT: Don’t read on if you haven’t watched “Tunnel Vision,” the final episode of “CSI: Vegas” that aired on Sunday, May 19. “Things are about to go kaboom.” That’s what Beau (Lex Medlin) says on Friday night’s series finale of “CSI: Vegas” as he prepares to detonate a series of bombs. But he might be describing everyone’s minds, as the show’s characters discover midway through the episode (“Tunnel Vision”) that they’ve been chasing the wrong villain all season.