Ah yeah, perhaps it is a bit late but I should have added warnings about persecution of heresy and warped religion-like setting. I know that it sounds a bit odd for a fanfick about giant sentient robots but hey, consider being warned.
I like to imagine that Cybertron has flora and fauna because of course it does.

They were strolling through the Ankmor park - one of the few areas where members of all castes could enter freely. One of the noblemechs had left the park to the city after his death under condition that everyone was allowed to frequent it. Thought the name 'park' was deceiving, it was more of a botanical garden than a park. Various examples of metalloid flora grew there, each labelled in accordance to their taxonomic name and place of origin. The specimens varied from fairly common nickelillies to such rarities as a giant crystalline cypress which dwarfed even Megatron. They stopped by a pond which housed several types of floating crystals, suspended in carbon monoxide.
-"I was serious about archaeology. You see, it is a risky business even for a beginner such as myself." Away from work Orion looked much less guarded and if anything, more genuine.
-"I hardly have the authority to protect you from Church's persecution." Megatron was not going to let go of Orion's little prank earlier that day any time soon. Even though he understood that the archivist had done so to protect himself and the rest of mechs involved in his little archaeology escapades. If Megatron's identity and past relations to church were anything to go by. The mental workings behind this 'proof' were a bit unclear to him.
-"That may be true but you are strong enough to keep away those with a more hands-on approach."
Orion chose to move from their spot at the pond. Megatron quirked an optic ridge and followed suit. Probably the archivist wanted to shift around to avoid being overheard or followed. -"You wish to take me out to conduct field work with you?"
-"Or as it stands, watch my back." Orion added his eyes flaring blue as they passed under a shade of a weeping weld-tree. Megatron shuttered his optics excusing this as tricks of light, no bot had blue eyes.
-"I am not sure how familiar you are with gladiatorial code, but by no means are we free mechs."
-"Care to enlighten me?"
It had been worse than Orion expected - Megatron was technically a glorified slave, an asset. Eventually he could buy himself freedom but he would still have to live long enough to earn it.
-"I think I must apologize for more than I initially thought, Megatron. I truly had no understanding of your situation." No wonder the gladiator had become so hostile.
Megatron shrugged -"Making amends will not change my predicament."
-" Maybe, but if more mechs knew, I think you would find more mechs willing to take your side." Orion caught a glimpse of something in the optics of the gladiator. He probably had already tried; the archivist vented in frustration felt on behalf of his companion and cleared his throat.
-" I must apologise for making it sound like I am about to do a business transaction but do you think I could, uh, rent your services for couple of days at a time?"
Megatron snorted - it was not up to him to decide, due to his popularity his owner usually demanded a steep price of whoever wanted to encounter the gladiator outside the arena. Judging by Orion's place of employment, chances were - he would not be able to afford it.

Ratchet and Orion were discussing the matter of Megatron's assistance privately in the early hours of the morning following their meeting. The Archivist had caught up with the medic after he had done his rounds on making checkups on his sole resident patient.
- " If he was faking, he definitely did a good job of that."
Before Ratchet managed responding he was interrupted by his apprentice who, judging by his state, had just come out from recharge. A thermal sheet was snugly wrapped around him to ward off the chill of the morning. Kerosene models were far more susceptible to low temperatures.
-"How is the patient doing and also, who was the wise guy who thought this was a good idea?" Knock Out hovered in the doorway, waspy before his morning refuel. The target of his displeasure this time was a large tarp-covered crate that sat at the entrance to the medical ward. A meek chirp sounded from under it. If anything, that caught Soundwave's attention immediately. He strained his body to move but the world before him spun in a dizzying array of blazing lights and dark dots. It was like watching fireworks in his own head.
-" Stay down, or I will tie you to the berth." Ratchet gruffed. They heard another chirp, this time more insistent as Knock Out had lifted the edge of the tarp to look inside.
-" Pretty bird. Let me guess - Nautilus's shadow?"
Lazerbeak puffed out her metallic quills, they could hear them rattle together as she preened under attention.
-"Megatron passed by this morning and insisted that I bring her here."
The red trainee medic looked from Soundwave to his avian companion, they were an odd pair. Nautilus was a submarine, his sleek yet angular shapes honed to reduce drag when submerged whilst his pet was a flyer. Ratchet was about to say something but Knock Out cleared his throat daintily to draw everyone's attention.
-" Seeing as there are no other patients currently in the ward and if our patient behaves, perhaps we can allow him to keep company?"
-" That is not your decision to make, colleague." Ratchet replied matter of factly. He would need to seek head nurse's approval and she was a strict little creature.
-" Surely it is only a suggestion, I amaware of the sanitary concerns, but it might help with recovery better than being tied to bed?" The red mech smirked. -" In fact, I was hoping for your support in the matter."
-" Only if you personally give that bird a decontamination bath." Sounded a stern little voice behind them. They turned to look at the petite blue-framed bot that looked far too slight to even exist.
-" Ah, head nurse. Glad to see you here."
-" You better get ready for your morning sermon, Scarlet." She turned her attention to the remaining bots in the room. -" What are you two even doing here? The patient needs rest. You can discuss matters elsewhere."
Ratchet waved his goodbyes and headed towards his lab and Knock Out pulled Orion to the side. Orion had initially thought that it was for care instructions but Knock Out was far more concerned with matters of privacy.
-"I can't believe you let him know where you live! That is suicidal!" The red grounder whispered with a mix of worry and anger.
-"No, we met at an appointed spot not far from the gladiatorial quarters, you see, he is not a free mech."
Knock Out snorted at that. -"Don't tell me this is news for you."
-"I did not know the full extent of it, that varies from owner to owner." Orion stated defensively.
-"Look, I know you feel strongly for the oppressed, Orion, but you trust too easily. Let Bumblebee do more research before laying out your cards." With that the red grounder picked up the crate and turned to march to his office.
-"Ah, wait, Knock Out, the care instructions?"
The carmine grounder turned to look over his shoulder smirking. -" Let me guess, solvent that is not too harsh, temperature slightly higher than for us large mechs and what else?"
-" A brush." Orion finished providing the instrument, smiling. -"Take good care of her."
-"Of course, she's got me as a caretaker." Knock Out lifted the crate to his optic level so that he could look at Laserbeak directly. -"You lucky bird you."

Nobody listens to poor Soundwave