Just went back and listened to 11-1 since there was a physical description of "Pinstripes" in the Tower:
6 and a half feet tall, broken and crooked teeth, skin covered in tattoo, bright green eyes.

Puck's description in 42-3: white teeth against his dark ink face

We've had a bunch of discussions about the apparent differences in behavior between Pinstripes in the tower in Chapter 11 and Ink/TOWTM in other encounters. This, to my thinking anyway, might hint back to their being some difference between the two. Not going to beat the horse too much but just bringing it up to say that it might have been another experiment that Roberts was doing.

He obviously was doing lots of physical experiments on mostly criminals, some definitely violent. What if he was also doing some experiments on another group looking for intelligence? I think we are supposed to assume that the Little Ones are smarter than your average Zed (see "Red Winter", "It Only Takes One", and some other episodes) and the oft repeated mantra from Burt in Season 1: "The smarter you are in life...."

It makes sense to me that he could have intelligence trials too. The zombie change by nature gives some enhanced physical characteristics. Pick a likely candidate, give him the "thinker" drug cocktail, dress him up in a nice suit (and body armor), and send him to see if he can infiltrate the Tower.

Maybe a little to for some, but it seems in the realm of plausibility.....