I just rewatched The Secrets of the Engine Pt. 3 and thought 'Okay. Soooo who's going to tell X that Speed was using his own oxygen to fuel his car?' Apparently Schwarz wasn't going to give us that, so I decided to!

"Do you know how risky that was?!" X shouted in agitation and near hysteria. "You could have died!"

Speed, the receiver of X's near hysteria, flinched slightly. He and X were in X's room with Speed sitting on X's bed and X standing over Speed and yelling. Even after all his time with his brother, X's concern over Speed's well-being was something to get used to. Of course, somehow, X got wind that Speed had used the oxygen in his cabin to fuel his tank, and the older brother had flipped his lid. X looked ready to strangle someone, and Speed was really hoping it wouldn't be him or the doctor.

"But I didn't. Isn't that what's important?" Speed asked.

X's eyes seemed to have widen at that, and Speed later regretted saying it. Perhaps he should have just apologized instead of defend himself.

"Speed! Do you even realize the danger you had been in?! If I hadn't turned back to save your butt, you could have died!" X snapped.

"But you did! So see, everything's fine. I'm even breathing oxygen in as we speak," Speed said, hoping to appeal to X's ego.

X narrowed his eyes in annoyance.

"Speed, you need to take this seriously! Your life is way more important than a race!" X responded.

Speed lowered his head and mumbled under his breath,

"I seem to recall you not dropping out of a race with a bomb in your nitro system."

X's eyes narrowed more in annoyance, but he didn't comment on the matter. This wasn't about that past situation; it was about Speed and his recklessness in regards to his own life. He took a few moments to breathe in, calming his nerves before he did something drastic. For some reason, Speed didn't seem to understand how upset X had been about the situation. Yeah, he had gotten upset when he saw Annalise and the twins almost run Speed off the track...but had he known Speed was losing oxygen, he would have done things differently. He sat down next to his brother and released a heavy sigh.

"Speed, I need you to tell me when you're in trouble, or if you need my assistance."

"I just didn't want to ruin your chance at impressing Turbo," Speed responded, not looking up at his brother.

There was no malice behind his words. There were a number of reasons why he didn't ask for X's help. Pride was the main one. Wanting X to impress Turbo was the second one. The last was that he was still getting used to asking for assistance in a race.

"Speed, we've been through a lot, you more than me," X said, sounding as calm as he could. "But you need to understand that I wouldn't be able to live with myself if you got seriously hurt, especially if there was some way that I could help you." He paused once more to collect himself. "You and I are all we have, and I'm not about to lose you just when I've found you, okay? So I need you to tell me when you need my help, especially if you're about to get hurt, or do something stupid and use your own oxygen as fuel, okay?"

Speed nodded, smiling at his brother.

"I will, okay? And you need to do the same to me. I don't want to lose you either."

"Dude, I don't get into nearly as much trouble as you," X said, "but I promise I'll ask for your assistance if I need it. Deal?"

"Deal," Speed said with a grin.

"Good. And if I hear you do another stupid stunt like using your own oxygen as fuel, I'm going to beat you, got it?" X questioned.

Speed chuckled, not taking X's threat seriously. Oh sure, he'd probably get another talk to from X, but Speed knew his brother would never hurt him.

"Got it bro."