Go wherever you like to go? i have many ex colleagues who left big 4 before 2 years and most are doing ok and happy with their lives.

Who said must stay for 3 years? Your manager or partner ah? Most managers are just making use of you and are afraid of losing seniors so they want you to stay for 5 years.

There are too many risk adverse sheeps in big 4 who just blindly follow what their peers or managers are saying. This is also the reason why big 4 culture will never change because most are conservative, pessimistic, risk adverse and afraid of changes.