Reina was sent off for a head butt while Carroll appeared incensed to be substituted.
“The frustration and disappointment resulted in the actions Pepe took when he got a deserved red card,” he said. “Andy came off and went up the tunnel. He was frustrated with the way the game had gone. Not just for himself, but for the team.
“We have not got a problem with people showing desperation or disappointment or frustration, but we need to channel it better.”