Generally speaking, it was a rule to avoid the comments section of any battle where Batman lost. The angry fans on those parts of the internet would drive most people to despise the Bat's fanbase.
Another comment section to avoid would be any battle involving a pony that wasn't Pinkie Pie. The amount of people who were very anti-pony would make the bat fanboys look marginally mature considering that there was at least one person who claimed that the only reason Black Panther won was because the battle was released during Black History month.
Overall though, there was no rule that said to avoid engaging in a battle against Shredder and Silver Samurai without proper backup.
"DONNIE!" Leonardo called out as his purple-masked brother vaulted over his shell and performed an overhead strike against Harada.
Michelangelo followed suit, using his nunchaku to snag at Silver Samurai's blade and tear it away from him.
"Bah! Blasted reptiles!" Silver Samurai took out his throwing knives and threw them at his opponents.
The turtles managed to avoid them all, but the tachyon field had already enveloped the blades and made clean slices in the building that was behind them.
"Watch out! Those things are sharp!" Michelangelo called out.
"Technically, it's the tachyon field that makes it sharp." Donatello pointed out, "If only his hatred for Wolverine wasn't as big as it was, I could get a closer look at it and study it."
"Family squabbles are hard to let go…"
"Whatever!" Raphael snarled, "Let's take this guy down now!"
"Turtle power!" Michelangelo called out, as the others attacked in suit. First was the party dude himself. Striking at Harada hard enough to send him reeling into Raphael's assault of stabbing Harada in his exposed areas, and twisting his blades to crack Silver Samurai's arm.
"AUGH!"
"Coming through!" Donatello came in and tripped his opponent by swiping at his legs and sending him into the air.
"Here we go!" Leonardo performed two powerful slashes at his foe's torso and managed to create two vertical holes in the armor.
"That armor isn't so tough." Michelangelo pointed out.
"Yeah… it almost makes it feel like-"
"MUWA HAHAHAHA AHAHAHAHA HA!"
Several Fulgore units appeared. All of which had a foot clan logo on their chest, and were all ready to do battle.
"A trap…" Donatello finished as another opponent started walking towards them.
The Silver Samurai that they fought exploded and sent mechanical parts at the world's most fearsome fighting team.
"Excellent job, Harada." Shredder commented.
"It is of no concern. Perhaps these reptiles will lead the Wolverine here when they call for backup."
"Well now it is time to dine on turtle soup!" Shredder declared as he jumped forward and prepared a swing.
*SPLOOSH!*
"Great job Blastoise!" Red called out as he got ready for a fight, "Alright, go Charizard! Venusaur!" The two other Pokémon were summoned from their balls as they roared for battle.
"Red! Dude!" Michelangelo called out, "Thanks for the assist!"
"No problem." Red gave them a thumbs up, "Blastoise! Give them some backup! Venusaur, use vine whip to throw the fulgore units around!"
"SAUR!" The seed Pokémon followed his trainer's orders as he used his powerful vines to grab at a Fulgore unit and threw it into another.
"HARADA!" Shredder called out as he recovered from his sudden shower, "TAKE CARE OF THE TRAINER! THE TURTLES ARE MINE!"
Silver Samurai nodded as he rushed forward to use one of his mighty attacks on the trainer.
"Ahh!" Harada was stopped by a sudden burst of flame as Red's mighty Charizard landed and Red mounted his trusted Pokémon.
"Alright Charizard!" Red pointed, "Let's give him a fight! Venusaur! Keep taking those Fulgore units down!"
Venusaur nodded as his razor leaves started bombarding the UltraTech enforcer robots with its razor sharp leaves.
"BAH! Stop standing around you useless machines!" Shredder barked, "ATTACK!"
The Fulgore units started forward. Only one of them managing to make it nearby Venusaur without being thrown by the vine whips
"Venusaur!" The seed Pokémon cried out in pain as it was attacked by the Fulgore's plasma claws.
"'STOISE!" Blastoise had blasted the unit away with a powerful burst of water. The two Pokémon nodded as they readied to team up and stop the Fulgore units from reaching either Red or the other Turtles.
"That's great Blastoise!" Leonardo called out, "We can handle old Shred-head from here. You keep giving Venusaur that backup!"
"I do have to wonder though…" Donatello trailed off, "where are Wolverine and Raiden? - Shouldn't they be back from that mission?"
"Let me tell it to ya slowly." Logan snarled to the guard, "I can't remove the metal. Do you know who I am?"
"I honestly don't. I make it a point to not know any overrated comic book characters." The guard replied, "And the second game ruined Metal Gear for me, so I also don't know who he is."
"You're an idiot." Logan deadpanned, "and I want to talk with your manager."
"I am the manager." The guard replied, "Look, if it means anything, there's someone around who actually does like you overrated lot, and maybe he can help you out."
"The hell with this!" The mutant snarled as he stormed off, "I'm getting a drink!"
"Wow…" Raiden noted, "Not even McGinnis can rile him up like that.
"Well, wherever they are, I'm sure that they're doing something important." Leonardo said, giving the two blade using war veterans the benefit of the doubt.
"Don't matter!" Raphael snarled, "We got a Shredder to shred!"
"Raph's right!" Donatello added, "Let's go!"
"RAGH!" Leonardo struck at Shredder with his swords in an overhead strike that staggered their opponent.
"Coming through dudes!" Michelangelo called out as he struck at Shredder's legs from behind on his skateboard.
Having kicked it upwards, Raphael threw his sais at Oroku Saki and also kicked the skateboard towards Shredder.
Having staggered Shredder once again, Donatello struck overhead, sending the Shredder skywards, all other turtles in position, all of them managed to slam Shredder with their shells once he got up after he landed back down.
"SHELL SHOCKED!"
With Shredder defeated, the other Turtles looked at their friends.
"LET'S GO! TRIPLE FINISH!" Red called out as Charizard used Fire Blast to strike at Harada and the remaining Fulgore units while Blastoise's Hydro Pump kept them away as Venusaur's Solar Beam kept dealing damage. Charizard shot one more Fire Blast and flung the Fulgore units away while Silver Samurai was flung into a wall.
Harada barely managed to get back up as he pressed a few buttons on his device.
A new robot came down and picked up both of the living combatants.
"Next time, turtles, you will not be so lucky!" The robot flew away with Silver Samurai and Shredder. Presumably, they were retreating to lick their wounds.
"I'd call it more skill rather than luck." Leonardo answered.
"Hey guys! We're right next to a pizza joint!" Michelangelo pointed out, "Celebratory slice?"
"Alright!"
"Red, you want a slice?"
"Nah." The trainer answered, "I gotta get back to get my guys recovered. You have fun though!"
"Cool."
X: So I have this new method of writing where I have a bunch of chapters on the backburner wherein I make chapters in advance with characters I'm anticipating will enter DEATH BATTLE.
Wade: Why bring this up?
X: Because I lost all respect for Batman when a few of his fanboys claimed that the primary reason Black Panther won was because the battle was released during Black History Month, so when I do the chapter where Black Cat and Catwoman show up, people know that was back when I still respected the overrated flying rat.