The first time the team fought Trex. They may not be (combat grade) bots yet, but they're well on their way.
"Under Pressure" - Blades, without prompting and even against recommendation, flies headlong and blinded through a cloud of volcanic ash to get the water to save Cody, knowing full well the ash could gum up his rotors and drop him from the sky. He doesn't make a big deal out of it either (he wordlessly takes off once he understands the situation) and it isn't portrayed as the epic "overcoming his fear" moment most shows go for. He's just buckling down and getting the job done regardless of his terror. Rescue Bot, yes he is.
Also, Heatwave and Kade putting aside their differences to protect the one thing they have in common: Cody.
"Deep Trouble": Heatwave wrestles a sophisticated robotic shark-like submarine, and considers it a sport.
Chase gets a small one in "Christmas in July" when the Mayor tries using his radio to take credit for Cody's idea.
Chase: Mayor or no mayor, he's not telling a lie over my public address system.
You tell um Chase.
In "The Reign of Morocco", after Cody, Dani and Blades are caught spying on the good doctor. The Morbot chases them all the way back to the fire station, where the other Rescue Bots stand ready. A fight is averted when Dr. Morocco calls the Morbot back to the lab. Still, it was pretty awesome watching the bots ready for a fight. They may not be (warrior class) bots like Optimus Prime's team. But they're still Autobots at the core.
Not to mention the Morbot's analysis of the ever increasing threat level of the team. Loved it when it reached Heatwave, and went off the charts.
Chase in "Rules and Regulations", mostly for refusing to follow Heatwave in disobeying the chiefs' orders, and faking a littering emergency to get the human half of the team to come help after losing contact with the other bots.
The scene where Chase used an inflatable bubble tent to save Heatwave from an erupting geyser.
Heatwave: I guess rules can be useful once in a while.