“If you can’t stand the heat, get out of the kitchen.”

The expression means if you can’t handle a difficult situation, then leave. In other words, if somebody can’t handle the pressure, they should just quit.
Example: The students argued that the course was too demanding. The teachers said that if they couldn’t stand the heat, they should get out of the kitchen.”
Source: ‘Know Your English’ ( The Hindu) -April 02, 2007