Not sure who Sherman on the Bengals is, but what I think you're referring to is a "fair catch"? From my understanding of what happened from what you're saying is, Steelers kicked the ball off, during this time, the kick returner can either catch the ball and run, let it hit the ground, or signal for a "fair catch". A fair catch is signaled when the kick returner waves both hands in the air, this means that the kick returner has the ability to catch the ball with out interference(kicking team can't tackle the kick returner when he catches it or recover the ball unless someone on the returning team touches it first) and then the ball becomes downed at the spot where he catches it.
So during that play, I think what happened was Tate signaled for a fair catch, but someone else on his team got the ball and started running with it? By rule since Tate signaled for a fair catch, the ball is downed where ever it is caught. The other player that caught it (Sherman?) probably didn't know Tate signaled for a fair catch, so he just ran with it. But in a case like this, the refs would just blow the play dead instead of throwing a penalty, so this might not be what you're referring to, but idk.