well, if he was going for the kill...
deidara had problems with sasuke's speed, he needed madara to the c2, and it took kinda long, if sasuke had decided to kill deidara, i bet that he would do the kirin faster than deidara and tobi prepared the c2 xD
deidara would go crazy using the bombs to stop him, and only madara would help him kill sasuke so, only the c2 would stop sasuke's shunshin, and sasuke still had the option to fly