What happens if I can't finish series on time?

http://web2.assist.org/web-assist/report.do?agreement=aa&reportPath=REPORT_2&reportScript=Rep2.pl&event=19&dir=1&sia=DAC&ria=UCLA&ia=DAC&oia=UCLA&aay=16-17&ay=16-17&dora=CELL+MOL says the following:

I.e. the physics sequence is strongly recommended, but not absolutely required. However, due to the level of competition, others applicants with physics complete may have an advantage.