Beeping Truck Conversation

So, we're eating snack today and Elsa says, "beep beep" and I ask her what she is talking about because it seems like a random thing to say. Then I hear the recycle truck in the neighborhood backing up. I then attempt to explain why the truck beeps:

Dad: "Elsa, the truck beeps when its backing up"
Dad: "If the truck didn't beep, then someone might get hit" Unfortunately, I dramatized this with my left hand as the truck and my right index finger as the ill-fated person. "If this is the truck and it backs up..." Then, "OH NO" the index finger gets squashed. She seemed to understand, which made me worried that I overdid it, so I tried to salvage the situation.
Dad: "Elsa, the truck beeps so that if a dog is behind the truck, they can get out of the way."
Elsa: "Woof Woof"

The rest of snack was funny, but regrettable.

Elsa: "beep beep" ... "oh no!"
Dad: laughing... and wishing he hadn't explained why trucks beep.
Elsa: "beep beep" ... "oh no!"
Dad: laughing... trying to hide it.
later...
Elsa: "beep beep" ... "woof woof"
still later...
Elsa: "beep beep" ... "oh no"
later still...
Elsa: "beep beep" ... "woof woof"

Question: Have I damaged my 20 month-old daughter with too many literal explanations of how and why things are the way they are?