The way your code works:-
Read switch
if switch on
light leds in sequence ( with delays )
else
clear led's ( no delays )
So if you turn off your brake lights as you are entering the switch on branch of code... The LED's wont shut off until the on sequence has finished.... Three 200mS delays = 600mS so potentially you could see up to 600mS delay after turning off your brake lights.... If you use a buffer... It will be instant as you are not writing to the port every cycle...