L.N.
i can relate to that.
this will be lost in translation, but when we would fall down as kids, my mom would say: direct translation into english 'i hope it hurts.' which meant, she gave us the warning to be careful, we didn't listen, so if we fell down and it hurt us then we would remember to be careful next time as her warnings were not enough.
i get scared when my kids fall and i squeal, i don't know how else to explain it, but it's a unintentional yell. as in my heart stops OH MY GOD. but my kids didn't like it. they thought i was being mad. i didn't understand why they didn't like my 'squeal.' so i know it's a cultural difference, and i am trying my best not to vocalize my fear. and i say i am sorry if i have vocalized it. and then i explain that it hurts me more than it hurts them hence my 'squeal'
of course now my 5 year olds say oh don't worry mommy is not english (hahahah). but working on it.
start by saying i am sorry after the yell. also explain that you just hurt because he got hurt. that is why you yelled.