Advice on Changing Pads in a Parking lot

Thanks for the suggestions, I'm waiting for it not to be 90+ degrees outside, then I'll try to loosen the bleeder screw (i think thats the key) and pop the top from the master cylinder. I'll try the screwdriver method, if that doesn't work, I'll grab those c clamps. I'm actually fairly familiar with the KH calipers, I had to replace them after losing a pad at 70 mph (hyperextended its piston, real fun story at parties)