This is a small alternate scene in "Mutant Gangland" where Slash helps find Raphael. I always felt like the opportunity for Slash and Raph to have a heart to heart was missed from this episode.
It is a hard time for the Turtles, as well as the Mighty Mutanimals. Don Vizioso and his goons have all sorts of weapons at their disposal, specifically designed to wipe out mutant kind, no matter what form they come in. To make matters worse, Raphael has, once again, gone on a warpath and quit the team, setting off on his own. The timing could not be worse.
Logically, there is one solution… divide and conquer. While Leo, Mikey, Leatherhead, and Dr. Rockwell go to Vizioso to try to negotiate, Donnie, Mondo, and Slash go to look for Raph and try to talk sense into him.
Slash is jumping from rooftop to rooftop trying to search for Raph. So far, no luck. C'mon Raph, where could ya be? From there, Slash is starting to get worried. He might not be Raph's pet turtle anymore, but he is still his friend, and he was going to find him. Finally, his luck changes, for there Raph is, storming along the rooftops. Time to make his move.
"Stupid Donnie, he's got some nerve finding me!" Grumbled Raph. Apparently, Donnie and Mondo found him. It seems that their attempt to talk to him did not go too well. "Whatever, I don't need him. I don't need any of them."
"Does that include an old friend?" Said Slash, as he approaches Raphael to converse with him. "What's eatin' ya Raph?"
Part of Raph wants to scream at the top of his lungs to get everyone to leave him alone. Yet, he is unable bring himself too, much less to his former pet turtle companion.
"Please slash, just go." Raph said. "I really don't want to talk about it."
"Funny, you could always talk to me before, when I wasn't a mutant. Why not now?" Slash makes an excellent point. When Raph was really frustrated or sad, there was only one friend in the entire world he would ever share his feelings with. That was indeed Slash before his mutant days, back then known as Spike. Just because he is a mutant now, that does not mean he cannot talk to him now.
"It's just my brothers and… even my sensei. They just don't get it! Enemies out here are getting tougher and tougher, and we were still training with kid gloves!" Raph then walks to the edge of the rooftop to sit, wearing a grumpy expression. "All I wanted was to fight for real, and that makes me the bad guy. I'm always the bad guy."
"You don't think I felt that way once?" Slash said, as he moves in to sit next to Raph. "You remember the first time I got mutated? I had nothing but rage toward your brothers. Not just because Donnie almost accidentally blasted me into smithereens, but also because you always told me they were holding you back." Slash starts rubbing his own wrist, for these are not memories he particularly likes to remember. "And as such… I became a monster and tried to kill them. Is that what you're aiming to be? A resentful monster?"
"No, of course not!" Raph said, feeling defensive. "I never said I wanted to hurt my brothers! Even though I… was really fighting hard against Leo… almost severely injured him...during training." Now Raph understands what the others were trying to tell him. This is not the first time he let his anger get out of control, but this is slightly different. This time, he meant to hurt Leo. Raph feels guilty by this point.
"Now do you get it Raph? Don't get me wrong, I agree you gotta train harder to be better, but that's not worth losing family over. Your brothers, they'll always have your back. Isn't that more important?"
Raph starts to think long and hard about that for a moment. Sure, the bad guys are getting stronger, and as such they must train harder. But, the key word there is training. They train to get better in combat and to increase their chances of victory, not for the sole purpose of doing harm to others, much less family members who are always there for him.
"You're right, Spi… I mean Slash. Thanks for the pep talk."
"Anytime."
And just like that they exchange bro hugs. Slash kind of finds it funny that Raph almost called him Spike. Just like old times, only now, Slash can communicate with him and express himself.
"So, we should probably find Donnie and Mondo. I think they were a couple of blocks ba—" Raph's sentence is cut short when both heard a rather large explosion nearby. And, much to the horror of the mutant turtles, it was in that exact direction that Donnie and Mondo were in.
That's pretty much it here, I'll leave the rest to imagination. Feel free to tell me your thoughts, hope you enjoyed.