Um, in the real world everything happens fast. I can assure you based on years of military and contract security work , training with the best special ops in the world and being in very close quarters with the enemy in Iraq ,Yemen, Ukraine and Belarus among others if you think you can punch out when you are grabbed it is best if you stay in your school. A trained man can throw you upon contact. It happens just as fast if not faster than you can punch.
Personally I have trained in Sambo and JJ for about 20years and my Kwai family wing chun close range skills have saved my life more than once.
This is why it is advisable to cross train. Wing chun is not grappling- it is hitting. If you find yourself grappling then you had best be doing something that is useful for grappling. Wing chun is blatantly not