I'd say coincidence. He wanted to bring RSC in to give us an extra dimension up front, it could have been anyone but he's swapped him for Bridge a couple of times before this game. SWP was dire and taking him off for Johnson was the obvious (and point clinching) substitution, and Micah was in danger of getting sent off.
Interesting though that it ended up being the 'Miami 3'.
Didnt even register with me when it occurred, I doubt that was Mancini's reckoning. If that was his way of punishing them then its diabolical managing on his part, you dont punish them during a match