With “Hair Patrol.” the tenth episode of the DC Universe original streaming series Doom Patrol, “showrunner” Jeremy Carver and co. have decided to go back and fill in some of the blanks — not only in terms of what everyone else got up to while Brendan Fraser/Riley Shanahan’s Cliff Steele and Diane Guerrero’s “Crazy” Jane were struggling to find their way out of the tormented and fragmented subconscious of one Kay Challis, but in a larger sense. As in — what, exactly, is the deal with Timothy Dalton’s “Chief” Niles Caulder?

Not that Eric Dietel’s script gives away all the answers, of course — not even close — but in the wilds of the Yukon Territory way back in 1913, Caulder had a life-changing experience. One that ties him in with an earlier version of the Bureau Of Normalcy, sees him match wits with a colleague-turned-enemy named Alistair (played…