system
A chat on subreddit /r/NoStupidQuestions
human
2 people doing cpr for 10 minutes would be exhausting.  If you know how to do CPR offer to help!

I will never forget being on our Christmas cruise for work with so many trained nurses and hospital personnel watching as 2 people attempted to do CPR on some guy who arrested. They literally refused the help of a large number of trained people. It took such a long time for an ambulance to get to the wharf (we hadn't left). If you have been involved in a resuscitation in a hospital we literally have a line of people ready to do compressions or better yet a machine to do them because if you are too tired you won't be delivering effective chest compressions.
gpt
Yuppers, after about 2 or 3 minutes your compression efficiency drops significantly and you start to become a liability compared to the next trained person.