(Sorry for the late reply, was trying to think of something that would throw a wrench in the tender moment, lolz)
"You forget.....I wasn't exactly the warmest person when you guys brought me in" he replied unflinchingly; he knew he was a jerk to them more times than he probably wanted to be. But significant loss screws with a person's head, whether they want to admit it or not. "I know for a fact I would have been dead had you guys not rescued me from the Beastmen....I have just as much to be thankful to you for." Personally, he felt like he was eternally in their debt; if the Beastmen had gotten a hold of him that one day, it would have been all over for him. But Yoko and the others gave him a second chance, so he would try his damnedest not to screw it up.
He breathed a slight sigh, as if feeling a bit lost on where to go to from here. He imagined Yoko probably wanted to be alone, and he was about to say she should probably go get some rest when all of a sudden a low voice said rather pointedly, "Exodus......." The recovering renegade turned his head to see none other than Simon staring at him, a fire of anger and sadness burning in his eyes. "Ah, damn...." Exodus thought to himself as he realized what happened: Simon was listening in on their conversation and probably overheard Exodus' rationale for leaving Kamina to die.
"Simon" Exodus replied flatly, his somewhat empty gaze peering right into Simon's burning one. This perhaps the wrong thing to do in this situation; Simon's hands clenched as he then said, "You bastard.........You let him die.....Why?..." Exodus breathed out a sigh; so he was right, Simon had overheard him. "If you want to be black and white about it, then yes...." Exodus replied listlessly, perhaps a bit too coldly for the poor kid to handle, as Simon then stormed forward, grabbed the bandages over the warrior's chest and slammed him into the wall with surprising strength. "Kamina counted on you.......And you left to him die! Why, damn it!?!" he then shouted, tears starting to stream down his face.
Exodus just breathed out in exasperation; he knew the kid was stricken with grief, but now he was just being irrational. He and Simon just stared at each other before Exodus replied, "Simon, if you're asking me that question, then you know of the choice I was faced with..." At this Simon paused, blinking in confusion, "What....?" "It was either save Kamina or save Yoko; if I didn't act, one of them was going to die. I don't know fully why I did what I did...." but Simon then just shouted, "I don't care about your excuses! Why should you get to live...Kamina sacrificed everything, he rallied everyone to fight! You're nothing but a broken, bitter old man!" Exodus just stared at him blankly this whole time, letting the kid rant; he was acting out his anger, his outrage from the throes of depression. Exodus had kind of been the same way when Harbinger died and he was recovered from his injuries in Littner, though Simon was taking the insults a tad too far by suggesting he should have died in Kamina's place.