Following Mario Lemina's incident at West Ham that cost him the captaincy, Rayan Ait-Nouri was given a second yellow card in the aftermath of the 2-1 defeat at Molineux, as team-mates and staff held him back from an Ipswich player.
Matheus Cunha was also briefly involved as tempers flared and O'Neil is adamant he will not tolerate this ill-discipline.
"When the players step out of line, they're heavily punished by me," O'Neil said.
"I haven't seen it, but Rayan will know how I feel about it already because getting a second yellow card and being unavailable for next week's game can have catastrophic consequences.
"However much stress and however much pressure we're under at this moment, we need to keep control.
"You see that really a little bit where we go down to 10 men when Cunha comes off, and our centre midfielder goes and presses Ipswich's goalie, it's absolutely ludicrous. It's a ludicrous decision.