Reid took a careful seat beside his leader.

"Hotch, I think I know what Peter Lewis did to you, and I'm gonna try to help, so…" The young agent sounded tentative, but it was the slight edge of fear in his voice that hit Aaron hardest.

"Reid, I don't want you to do anything that might put you in danger. Anything. Do you understand? An-y-thing. That's a direct order."

Spencer paused. He was trying to go forward as gently as possible. It was encouraging to be reminded that Hotch's chief concern, as always, was for those around him. With a compassionate core that strong, I have to believe that no unsub, no twisted psychotherapy, could truly alter him. He tried not to let Hotch hear him swallow the lump in his throat. Drugs could overcome the natural tendency to protect others. A person can be changed over time, but Lewis was rushed. He couldn't have transformed Hotch's essential nature. I have to believe that.

"Hotch, please. I won't take any unnecessary risks. There is a trigger the unsub planted in you. I just want to test out the theory I have about how he did it. If I know more about that, maybe we can find a countermeasure that'll remove it." His tone became plaintive, almost sad. "I don't think you'd willingly hurt anyone, Hotch. I think you'd fight against it with everything you've got."

The response was almost a growl; filled with self-loathing. "I just attacked Morgan. Your trust is misplaced."

"No, it's not. Besides, it's a two-way street. I need you to trust me to do this without putting either of us in danger. That's all I'm asking."

Hotch was still focused on the carpet under his feet. "How are you going to defend yourself if I go off? Answer me that."

"I'll ask you to stop."

Hotch didn't know if the simplicity of Reid's answer was born of innocence or ignorance. Didn't matter. "No. Morgan fought back with all his strength. It almost wasn't enough. You don't get it, Reid. I…couldn't…stop."

"That's 'cause Morgan did fight back. I wouldn't." The young agent joined his boss in contemplating the floor. "I couldn't. I wouldn't stand a chance against you. You know it. You knew Morgan could defend himself. That's why you let yourself go."

"That's a pretty shaky theory to risk your life on, Reid."

"Do you remember what you felt like right before you attacked?"

A few beats of silence passed as Hotch savored his distaste for the emotions that had coursed through him in an unstoppable flood. "Angry. Furious."

"Morgan made you angry?"

"He pushed me."

It was Reid's turn to fall silent for a moment as he considered how the altercation began. "I think your trigger is auditory, Hotch, not tactile. Did Morgan say anything?"

"Yeah." He frowned. "I don't really remember."

"That's Lewis. He made sure you wouldn't recall the trigger, so it can set you off again and again. It wasn't anything special. Probably some phrase or word that he was sure would pop up in everyday conversation, resulting in multiple attacks."

Hotch leaned into his hands, burying his face. His youngest agent had just voiced his biggest fear. I'm a time bomb with a reusable fuse. A really common reusable fuse. "You need to get out of here, Reid. And stop talking to me. You might say…" His voice faltered, but recovered. "…the wrong thing."

Spencer didn't move. Side by side they remained, each lost in his own thoughts. At last, Reid broke the silence.

"I know we made a deal never to profile each other, Hotch, but I also know we all do it. We just don't talk about it. So here's the thing." He confronted the Unit Chief's profile; Aaron was still holding eye contact in abeyance. "Whenever Morgan walks into a room and you're there, your posture changes. It's subtle. Subconscious. You stand a little straighter. Your eyes narrow. It's almost undetectable. Morgan does the same. If you approach him, he kind of…I don't know…flexes. It's down on that primal level again: you challenge each other."

"Challenging's a lot different than attacking, Reid."

"I know, but the point is it's subliminal. That's where Lewis worked on you. You already noticed Morgan as a rival and when he pulled the trigger, it was irresistible. Those two things together set you off in a different way than if someone like me were to be the initiator."

Finally, Hotch turned, subjecting his teammate to a searching look. "Morgan may be more my physical equal, but I never want you to think you're somehow lesser, Reid. Not in my eyes. You have abilities that surpass anything I could ever hope to attain. I want you to know that."

It was what Spencer had hoped for. "Then trust me now, Hotch. You don't feel challenged by me physically, and it's that brute-force type of physicality that matters in primal terms. I'll know when to stop. Trust me," he repeated.

Aaron rubbed his eyes with both hands, trying to quiet his fear for this young man who was as brave as any of them, and smarter than all of them. After a few moments, he dropped his hands, regarding Reid with sad eyes. Spencer was feeling hopeful, but Hotch's next words made every organ in his body cringe.

"Do you have your gun with you?"

"I…uh…no! I don't need a gun to do this!"

"That's the only way I'll go along with whatever it is you're planning." Aaron took a deep breath, releasing it in a shudder. "Go downstairs. Get a gun from Rossi. He has mine from …from…the crime scene." His stomach turned at the memory. "Come back, show me it's loaded, and then I'll cooperate."

"But…"

"Take it or leave it, Reid. The only way we're doing this, the only way you're staying alone with me, is if you're armed."