I have always heard opiate od's are peaceful but are they really?

I don't know much about opiates and opioids I did have a year period where I was addicted to oxys and hydros but I knew my limit if I went above a certain dose I get very nauseous and unwell so I never went past it and hear people that have overdosed say it was peaceful I never really believed it fully bc of how nauseous i would get if i took too much but again I don't know much about it