I actually think that line is perfect. It’s right at the very start of the game and it’s establishing the character personalities to the player who may or may not be familiar with these characters. As the team flies in Slippy mentions something about needing to fine tune his systems check. Peppy calls out an enemy to Slippy, who has decided to take this terrible moment to fine tune his equipment. So he calls out to Fox to cover him, showing how he is such a detail oriented gear head that he finds it more important to fine tune equipment than to avoid getting shot. It shows he loves his work, but is a careless liability. Right at the start of the game. It even ties back in later when Falco is getting chased. He says something is wrong with his G-diffuser, even though in the intro he shrugged off the systems check and said everything was fine. So he takes a little damage, that’s when Slippy mocks him with “that’s why you don’t rush a systems check” reinforcing to himself that he was right. I think it’s a good little back and forth piece of writing that deserves a little more context than just the single line. All of it together really tells the player all they need to know about the members of the team in just the first level.