if your regular brakes are overheated, unless you're driving a corvette or some other car with an exotic e-brake setup, hitting the e-brake is actually going to get you LESS than hitting the regular brake pedal. reason? they use the SAME brakes! (well, the rear set of your normal brakes anyhow. with the exception being like i said, on the corvette, & possibly a very few others). your BEST bet is if you HAVE to do lots of quick hard stops like that, & don't already have metallic pads, get them. secondly, you could try cross-drilling your rotors to improve cooling (motorcycles & auto racers have been doing it successfully for years). when brakes are that overheated though, continuing to hold the pedal down will only increase the time it takes before you will be able to use them again. the sooner you let off, the sooner they'll cool, and the sooner they'll work again. they can cool down surprisingly fast, so if you have enough distance, let off the brakes for a second or two if you can, then re-apply. i know from experience that the amount of braking you'll get from your trans may slow you down a bit, but it wont bring you anywhere near a stop (i.e. if you're racing from light to light, & you're at 80 & realize you have no brakes, dropping the trans down into low might get you slowed down to about
65 before you go flying thru the intersection).