SAP Labs Probation period

My friend is working in SAP Labs as an associate engineer, she was on probation but her probation got extended due to her performance now her manager informed her if her performance isn’t great they will terminate her what is the best thing to do here, should she still try to work hard and retain the job and if so is it even possible that her manager would consider or should she willingly quit instead of taking the risk of getting fired which would be bad for her career. Also during background verification in subsequent jobs would this become a factor ?