They are fighting each other.
http://www.indystar.com/apps/pbcs.dll/article?AID=/20051126/SPORTS04/511260468/1088O'Neal and Jackson had been going back and forth on the court when they took it to the bench. The conversation escalated to where it drew attention from people in the area as the coaches were meeting outside the huddle. Teammates had to intervene and break things up.
http://www.pacersdigest.com/forums/showthread.php?t=16797I should mention that apparently after the swing, JO grabbed Jackson's face to keep him subdued, and I assume after that either Jack backed off, or someone stepped in between. I just don't know. TV people didn't say a word.