The coach broke down while defending Federico Valverde and Aurélien Tchouaméni, and revealed that a worse physical altercation between teammates happened during his playing career.
The Real Madrid head coach appeared before the media on Saturday in what those present at Ciudad Real Madrid described as the most charged, most emotional and most significant press conference of his four-month tenure. In the days before Sunday's El Clásico at Barcelona, a week in which two players had come to blows in training, one had been hospitalised and both had been fined €500,000, Arbeloa spoke for close to an hour and left almost nothing unsaid.
He opened on the Valverde-Tchouaméni incident, but quickly moved beyond the incident itself to what he described as the more serious wound.
"What happened in the Real Madrid dressing room should stay in the Real Madrid dressing room. That is what hurts me most. If things that happen in the dressing room are leaked, I think it is a betrayal of Real Madrid. An absolute act of disloyalty to this badge. And it is something that saddens me greatly."
He was asked directly whether he had identified the source of the leak.
"I do not work for the CIA or anything like that. I am not accusing the players, or anybody. There are many people around the Real Madrid first team and I am not here to point the finger at anyone. What happens in private conversations between me and my players will always stay there."
To put the incident in the context of what football dressing rooms actually contain, Arbeloa drew on his own experience. He did not name Craig Bellamy or Jon Arne Riise — the two former Liverpool teammates whose golf club altercation in 2007 has become one of the sport's most infamous dressing room stories — but his meaning was unmistakable to anyone who knows the story.
"I had a teammate who picked up a golf club and hit another player with it. These are situations that should not happen between teammates, but they have always happened everywhere. I am not justifying it, far from it. But I have experienced even worse situations. We had the bad luck that it ended with Fede getting a cut. That is more to do with bad luck than with what actually happened."
His defence of Valverde and Tchouaméni was where his voice first began to break. He invoked Juanito — the late, beloved Real Madrid winger of the 1970s and 80s, the club's emblematic figure of total commitment — to make a point about imperfection and forgiveness.
"I always give an example. For me, there is a player who is the paradigm of what a Real Madrid player should be, and that is Juanito. Did Juanito never make a mistake? He is the only player we sing about at every match, because he understood what Real Madrid is. Not only did he have extraordinary talent, but he defended this badge and left his soul on the pitch every game."
His voice cracked as he turned back to the present.
"I am not going to burn Valverde and Tchouaméni on a public bonfire, because they do not deserve it. Not either of them. For what they have done for this club during so many years. For these four months. For what they have shown me every day — both of them. Their commitment, their effort, their love for this shirt. I will not forget that."
He then turned to the broader volume of stories that have circulated about his management, his relationships with players and the internal dynamics at the club — and he was unequivocal.
"A lot of lies are being said. It is a lie that my players are not professional. It is a lie that my players have shown me a lack of respect — not one of them, not once. It is a lie that a player does not play because he has a problem with me, or because his life does not correspond to what a Real Madrid player's life should be. That is absolutely false."
He accepted personal accountability without qualification when pressed on whether he bore any responsibility for the incident itself.
"I am the responsible for everything that happens at Real Madrid. If you want to put the blame on someone — here I am."
On whether the dressing room was healthy despite everything that had been reported, he pushed back on the characterisation directly.
"Of course it is a healthy dressing room. Of course. It is not easy to accept two seasons without winning anything. That generates frustration and anger. But we have to use that frustration and anger to play a great match tomorrow. That is where all our energy has to go."
He confirmed Tchouaméni would be included in the squad for Sunday's fixture. Valverde, diagnosed with cranioencephalic trauma, remains unavailable.
The press conference will be remembered for its rawness. Arbeloa — a man managing his boyhood club in his first head coaching role, four months into a job that has involved almost nothing but crisis — stood at the podium and defended every player in his squad, accepted every line of blame, pointed no fingers and left with his dignity intact.
Whether he leaves with his job after Sunday is a different matter. The only future he said he was thinking about was ninety minutes at Camp Nou.