Why does my ps3 randomly beep 3 times and shuts off when I play BO2?

Being a newer game, It’s probably a more intense, high cpu usage, and several internal components running high all resulting to an overheat. Depending on what year you got you your PS3, the older models are prone to crash sooner and all together break down. I’m glad for you that it still turns on after this happens. Take some precautions to carefully internally clean any dust and replace any thermal paste on necessary parts where it’s in use. Hopefully you can find a good connection for someone reball any parts causing this issue so that it will play like when you first got it with no issues.