It had been his little secret. He would slip into her cockpit and just sit and talk, enjoying the comforting feminine voice that said nice things to him. Her leather seats were much more comfortable than anything in the base, so much so that sometimes he fell asleep there.
Sometimes she would read selected passages from her owner's manual, or assure him in that same comforting voice that friendly fire protocols were enabled. He would clutch his teddy bear tight and pretend she was his real girlfriend.
Sometimes they might go driving around a little and he would talk to her about everything going on at the base, and how maybe next time if she ever decided to shoot someone again that maybe she could shoot Tucker this time and it was okay because he was sure that nobody would mind.
Caboose knew Church would always be his best friend, but these little moments were some of his best memories of Blood Gulch.
When he got relocated to Rat's Nest and told he could work with the vehicles he had been so happy! He loved meeting new people, and there was a whole motorpool at his new base. But they never talked back to him. He would sit for hours and tell them all about Sheila and Church and the Reds, and Lopez. Even Doc and O'malley. But they never said a word.
He missed all his friends. The people here weren't half as nice.
One night, after everyone was asleep he took his blanket and his teddy bear and his favorite picture book and climbed into the cockpit of the friendliest looking tank. He pretended that Sheila was reading him a bedtime story and snuggled up on the seats - seats that were never quite as comfortable as hers had been - and looked through the pictures.
The next morning, he was startled awake by one of the Blues yelling at him for sleeping in the tank. As he was trying to climb out, he accidentally hit the auto-fire sequence button and the mean Blue got blown up.
That's when Principle Miller suggested they play the 'tie Caboose up and put in him the brig' game.