I read it as him trying to antagonise McArthur to the point where he punched him to get himself sent off. If you did that to players like Keane or Viera, even Balotelli - known combustible players - then presumably he felt 10v11 would probably be worth whatever ban he'd get for it.
All that seemed to occur was Pearson looking like a desperate manager willing to do anything to help his team win, and despite the players being afraid of him, if they don't start turning that into results soon they aren't going to have a chance of staying in the prem. Their next run of games is absolutely brutal, with Arsenal, Villa and Everton all away, before they get to play Chelsea, Man City away and Tottenham at WHL.