Pffft. Of course I can and do lose my temper. And there can be the occasional yelling match (we have two teen in the home after all), but that night we were facing a kid that was far from being capable of anything (remember - came from a school trip and had hardly slept). We sent them to bed and took a loooong walk.
We adults vented then - pun intended - and had a stern conversation the next day. When child was coherent again.