The words 'you can't' have him stopping in his tracks to turn back and face Reid. He's honed in, focused with needle sharp precision on just what the other has to say to redeem himself. Reid's defense will determine just how he'll handle this threat or if he was a threat at all.
So far just knowing Reid was indeed alone and came alone with no real way to contact back-up or help was putting him at more of an advantage. A good once over wasn't even necessary but he did so by instinct once the Profile indicated himself. No, he could probably break Reid like a brittle twig if he really wanted to.
He wouldn't completely underestimate him, there was a good chance he knew some way to defend himself. Some techniques didn't require any sort of strength it just required reflex and know-how. Helix knew this, he won many of his own fights in this way.
He narrowed his eyes, tense, considering if he seriously wanted to trust the man with his secrets or not. He didn't have much other choice, he already knew everything and he had not real intention of spilling blood over any of this. But he needed some insurance.
Helix stalked forward, quickly closing the gap between them (even if Reid decided to back up, he wouldn't have far to go till Helix crowded him back against the wall.) The man was significantly taller but Helix had his ways of intimidation, getting up close and personal or in the others face. Or just subtly indicating at a threat.
"Do you know what they called me? I was the Futile Row Strangler. For years I went unidentified. They couldn't follow my trail, couldn't sniff me out, had no idea what I looked like. I used my bare hands to kill. I don't need a weapon when I AM the weapon." He sneered, indigoes locking with Reid's own dark gaze as he stood uncomfortably close, invading his personal space.
"I was also known as the Hellhound in the ring and by those in the underground. They knew I killed for Jethro when anyone got out of line. They couldn't escape me." Of course, back then he'd had Jethro's informants and network at his disposal. He was going solely on Jethro's signals and orders to track down his prey.
Catching the hint yet Reid? If not, he was going to spell it out anyway. So after a nerve-racking pause.
"Fine. I'll take your word." A pause as something else lingered behind that acceptance. "But if you betray me I'll kill you. And you'd best believe you'll suffer first."
With that he was taking a few steps back giving the man enough room to breath. He was satisfied for now, keeping his eyes on the other as he shifted to give the man a clear route to run out the door if he wished.