Joey Porter was illegally on the field. He wasn’t checking on injured Antonio Brown, he was woofing with several Bengals players.
When Pacman Jones entered the scene he bumped a ref and got 15-yard penalty. This penalty turned what would have been a long field goal attempt into a much more manageable one.
The field goal was made and the Steelers won the game. Reports are that Steelers gave Porter a game ball for his illegal action.
— Timothy Pontzer (@timothy_pontzer) January 10, 2016
Here is the official rule.
Either or both team attendants and their helpers may enter the field to attend their team during a team timeout by either team. No other non-player may come on the field without the Referee’s permission, unless he is an incoming substitute (5-2-2).
During any team timeout, all playing rules continue in force. Representatives of either team are prohibited from entering the field unless they are incoming substitutes, or team attendants or trainers entering to provide for the welfare of a player, and any game-type activities are prohibited on the Field of Play.
Normally this rule isn’t enforced when a player is injured, but Porter was not attending to Brown, he was engaged with multiple Bengals players.
This is why Pacman Jones was so upset.
It should be noted that if Pacman would have just stayed away no penalty would have been called, but considering the rule it should have offsetting penalties or no fouls at all.