In chapter 7, when the pegasi arrive at the Gildsedale Plains, Firefly asks Lightning Bolt to confirm their location. She knows the situation is slightly tense and tries to lighten the mood by goofing up.
Lightning Bolt: (checking the map) Hmmm... according to these symbols, of ancient meaning I presume, weíre somewhere... here.
Firefly: Tell me something I donít know.
Lightning Bolt: Consuming large amounts of food may lead to indigestion problems.
Moments later, Derpy drops a little gem of her own.
Lightning Bolt: Supply bunkers at 11 oíclock.
Derpy: Shoot! Itís 1057 hours! Weíve got to hurry!
(Medley and Cloud Kicker chuckle)
Firefly's facehoof when Pinkie Pie says she's throwing a party for her team just before the mission to destroy The Burning Talon in chapter 9.
Rainbow Dash asking Firefly for a permission to begin their own party in chapter 10. Complete with a proper tone and a salute.
In chapter 14, before the battle for Cloudsdale begins:
Lightning Bolt: [...] But now, letís focus on whatís ahead. RIDE OUT!
Firefly: Uh... Thunder? Whatís with that yell all of a sudden?
Lightning Bolt: I thought we need a sort of battle cry, you know, to boost our spirits! Was it bad?
Shockwave's reaction to The Equestrians whipping out a laser cannon to fend off Gleipnir in Chapter 6?
Shockwave (grumbling) "How can the Allies have access to laser technology? It does not compute..."
In context, this annoyance is the greatest show of emotion the guy's had so far...and yet he still talks like the 'bot he's a Shout-Out to!
Heavy Cloud's musings toward Lightning Bolt and Cloud Kicker in Chapter 10a. The way he reacts implies that he thought Spitfire brought them to him, so he could, in his own words, "go out with them".
In Chapter 10b, Colgate uses her magic to hit Firecracker Burst with a snowball in order to reign her in after she gets a little TOO excited while fending off the Exiles with her fire magic. Made even better from the sheer Mood Whiplash, given how the narration details the burned Exiles wailing in agony and Firecracker cackling like a maniac...then the snowball goes splat! and the violent scene ends, complete with Firecracker Burst sheepishly blushing and apologizing for her behavior.
It's her tone that nails it. She acts more like she shouted in a library than burned a bunch of ponies to death.