"Angus, no."

"I'm not asking."

"Not asking?"

Mac's eyebrows climbed. "If you're looking for me to call you sir, that ship sailed the second time your psycho ex-partner figured out how to rope me into your … whatever this is."

"You know that's not what I meant."

"Do I, Dad? Because any time I've tried to figure out what's going on in your head, we've barreled straight into a misunderstanding."

"I meant we're not testing this formula on you."

Mac huffed a sigh. "I didn't mean … Okay, maybe it crossed my mind when I was talking to Jack, but it was just an impulse … one of those thoughts that leads you to what you're actually thinking."

"If it works, you're alright with Murdoc being a … what did you say before? A super soldier?"

Mac huffed a dramatic sigh. "No! But I don't see that we have a lot of choice. The test subject has to be someone whose capabilities are a known quantity. And you won't—"

"Of course I won't," Oversight snapped. "Not to you. But we can't use Murdoc," he said with a clipped finality.

A fleeting question passed through Mac's thoughts too quickly to grasp. Instead of chasing it, he said, "What do we do then?"

"I'd prefer to test it on myself."

"And if it kills you?"

"Well, then you'd have no one to pretend that you were actually a C biology student for anymore, would you?"

Mac smirked and shook his head, but flushed anyway. "Not an option, Dad."

His father frowned thoughtfully. "If we test it on me…"

"You're the one who knows the ins and outs of this!" Mac snapped. "If it doesn't work, then I get a dead partner and a dead father, and, oh yeah, I also get to die horribly because Murdoc and Walsh will make sure of it!"

James shook his head. "I know, son. I was just thinking that if it worked, it might get rid of…It doesn't matter though. You're right. We can't risk it."

Oh, wow. He's thinking about his cancer. Mac hadn't even thought of his father's illness. What if the KX formula could cure it?

He had a second where the almost groggy post-surgery conversation with Sully came back to him. That split second where he didn't know what the pathology on his tonsils said. He felt a flicker of the absolute blank panic he'd felt before she'd reassured him of his clean report.

He put his bandaged hand on his father's shoulder. "I'm sorry. That's a hell of a temptation." He swallowed. "What if…and I know you're not going to love this…but hear me out."

James waved a hand for him to continue.

"What if we weakened the formula and then tested it on me? Just a small amount. Then, if it's, you know, not making me bleed out, we could risk trying it out on you at a little higher dose. Then, maybe we could get Jack squared away, and—"

"Angus…"

Mac ran a hand through his hair. "I know it's a dangerous play, but you're right. If we just ambush Murdoc the next time he comes in here to goad us into engaging, and the formula works, we'd be responsible for creating a supervillain." He forced a laugh. "And I'm not that into comic books."

His father cracked a small smile. "That's a pleasant surprise. But, Angus…"

"I'm healthy. I mean, I just had surgery, and my hand is a mess, but other than that I'm good."

"And?"

"Well, not knowing for certain if the formula is ready, if we test it on someone with an already weakened system, who knows what the effects would be?"

James nodded slowly. It was a fair point. "I suppose we could try to…The initial research did show some promise with localized wound healing. We could possibly use it on your hand where you cut out that chip. That could let us—"

"Yes. Perfect. And if it works for that, we can…" He stopped, suddenly full of a sick certainty. "You weren't thinking about creating a supervillain. You don't think like that. And you weren't worried it would kill him because you're pretty sure you've got the formula right. So why not Murdoc?"

"Now isn't the time to Monday Morning Quarterback my decision making."

Mac paled as his half realized question from a few moments ago came into sharp focus. "Was he part of the original project? Was he a test subject?"

"You've seen what happened to the original test subjects," James snapped, but he didn't look Mac in the eyes.

Mac sat down hard on a filthy bench and put his head in his hands for a long moment. When he looked at his father again he knew his feelings were all over his face. "Why didn't you tell anyone?"

"It's not what you think."

"Why?" he persisted. "Because it might have been nice to know that the apparently indestructible killer who's been dogging my steps for the last half a decade actually is indestructible."

"He's not."

"Coulda fooled me!"

"Angus … the original tests. Not the videos you saw, but the DXS project in its scientific form … yes, we got close on one or two occasions. But the volunteers who didn't experience cardiac problems … they didn't get indestructible." James still wasn't looking at him.

"What did they get?"

James swallowed audibly and finally looked at Mac. "Cancer. Recurrent, multisystem cancer. Until recently, I thought maybe I had it beat, but I was wrong."

"You … You tested it on yourself?" Mac thought he might be sick.

"I'm a scientist, first and foremost."

"You can't just go testing experiments on yourself!"

One corner of James's mouth lifted. "Says the man who just offered himself up as a test subject."

Mac chewed his lip. "Fair point." He puffed out a long breath. "What's the over under on this version of the formula not being wildly carcinogenic?"

"Actually, the components responsible for that were what kept the major cardiac events at bay in our original research at DXS. Once they were removed, you got what you saw on Walsh's video files."

Mac cleared his throat and tasted blood again, but wasn't sure if it was his raw throat or how hard he'd been chewing his lip. "I guess that's sort of reassuring, except for the whole Murdoc-isn't-sick-so-what-does that-even-mean thing. Because if he's not sick, maybe he is indestructible."

"Maybe. I've actually been thinking about that." James got the look Mac knew meant he was about to put on his testing/teacher hat. Mac had always hated that but was doing his best not to let it bother him these days.

"Go on."

"What is cancer? On a purely cellular level?"

There it is, Mac thought ruefully. "It's a failure of cell death. The programming of apoptosis doesn't work and cells that should die to make room for new healthy cells grow out of control. More or less."

"Tell me again how that C in Bio wasn't for my benefit," James chuckled. "You're exactly correct. So, if cellular regeneration is how healing takes place, and a chemical shuts off your cells' ability to die, and perhaps you have a gene mutation here or there—"

Mac's head dropped to his chest for a second, then he started laughing. He couldn't help it. "Oh, oh, seriously, you—"

"What's so funny?"

"You made Evil Deadpool!"

"I don't know what that means."

Mac snickered, but made himself stop actively laughing. It was more nerves than humor anyway, he figured. "You know Deadpool. You wouldn't let me read the comics when I was a kid."

"You got me. But you know how I feel about a barrage of movie quotes on a mission."

"Which is why we need to get this figured out. Because Jack likes them just fine."

"Yes, well, I'm also anxious to wrap this up. It would be an excellent outcome to a less than ideal scenario if we discovered the cure to KX7's version of El Cancer," he said in a perfect deadpan.

Mac cracked up again, and this time he didn't care whether it was nerves or not. He peeled the bandage off his hand. "That'd be great. And hey, maybe it's the cure to El Everything." Mac stood to join his father at the counter he was working at.

James waved him back as he filled a syringe with a small amount of their current formula. "You'll want to have a seat. This stuff hurts like Hell."

Mac sighed and planted himself back on the bench. "Yeah, that tracks."