Hi there! This is an interesting idea. It's hard to find scenes that will be funny without context so I'll try to provide some before you read it.
The chapter opens up with Nathan (MC) fighting against several enemies. Once he beats them all, he falls to the ground, exhausted, and notices that the person that's supposed to train him, Rafael, is doing something, he shouldn't.
RTD is the name of the robots that were fighting against Nathan.
There were two thuds. As much as Nathan enjoyed fighting, he was beat. He collapsed to the ground to rest for a minute.
“Finally,” he muttered.
Eventually his need for water overcame his need for rest. He stood up and looked to his right. Then his jaw dropped.“You can’t be bloody serious. RAFAEL!” Nathan shouted.
“Freaking hell! No need to be so noisy, kid.” Rafael flinched.
“I knew that getting you a deck chair was the worst possible idea. You fell asleep, didn’t you?”
“WHAT?!” Rafael tried to fake outrage, but Nathan’s expression told him it wasn’t worth the effort. “Okay, I may have taken a little nap. A really, really tiny one.” Rafael showed a minuscule gap between his thumb and index finger.
“Oh really? Well, then how did you like the fight? The part you didn’t sleep through, I mean.”
“I loved it! You finally managed to kill all seven of them!”
Rafael was honestly amazed by the kid’s progress, but Nathan wasn’t having any of it. “I’m glad to hear that,” Nathan said, crossing his arms. “Could you humour me and tell me which part of the fight was your favourite?” The fact that they were standing at least thirty metres apart didn’t make the conversation any less weird than it already was.
“Um. . . the. . . the one where you killed the RTD? I mean. . .” Rafael scratched the back of his head.
There are many more gag moments in the novel, but this one I found pretty easy to understand without context.