Saving a turtle

So, when you have a son you have to do things that you would probably not do if you had only daughters.
Nathan left for work Sunday around 10:30 am, riding his bike. My hubby was at church and I was home not feeling too well (nothing new there.)
About 10 min later here comes Nathan saying he needed my help. He was riding his bike and saw this turtle stuck by the curb on a busy road.
So we get in the truck, he puts his bike on the back and off we go. We get the turtle on a five gallon bucket and drive to a park (by the river) down the road from the restaurant where he works. He frees the turtle by a pond. So far nothing to it right?
Then he puts the bucket back in the truck and tells me he wants do ride his bike from the park to work. I say "ok", he closes the passenger side door and I take off.
I am driving slowly cause the park is full of children and also cause I am not sure where the exit is. When, maybe a couple min later, I look in the rearview mirror, I see Nathan hanging from the back of the truck, holding on to I dunno what, he has this grin on his face like "what has mom done now?" Then it hits me: when he said I'll ride my bike and closed the door, I took off. I never gave him time to get the bike off the truck.
So, I drive slowly to a safe spot (still in the park), and pull over. He comes and says "very funny mom". I am known to play jokes and pranks all the time, but I told him that this time I had totally forgotten. It was not a joke. He got his bike and off he went.
Later I was thinking, what if I had taken off faster, or what if I had backed up instead of going foward, what if he had not had the agility of jumping on a moving truck?
My memory problem is not only putting me in jeopardy but now is putting others too.
I could have saved a turtle and hurt my son.
It's just hard to say "no" to your child all the time and not be a part of what they like to do ever cause of your health.
They grow up so fast and then it's all gone.