Just give it up 😆
Even if Lightning did go 50,000 miles per SECOND, that's still WAAAAAAYY faster than anything Jean could do. That is faster than "istantaneous". In the real world that we live in, istantantaneous" usually correlates to something happening in a second or a "split second"
There's nothing that we have built, that we can observe, that gives us an idea of how fast 50,000 miles a second is. At that speed, You could travel round trip from NY to Hong Kong, China 5 times in ONE second. That's an inconcievable speed. There is no real "lag'' involved unless someone can put out some CLEAR perameters of what the "speed of thought" is as opposed to 50,000 miles per second.
Even if Jean was to somehow ''break storms neck", a fully charged lightning bolt would be soon to follow coming at Jean at 50,000 miles a second thus KILLING her. Remember, Just because Storm is dead doesn't mean the thought she had was not carried out. Whatever "lag" in between Storm's thought and the lightning only leaves Jean with what, a millionth of a second to react??? 😆
That's still TOO FAST for her to do ANYTHING.
Unless someone can come with some clear perameters for Jean's speed as far as her TK, and Telepathic powers other than the vague ''Instantaneous", then it's still.....
Jean DIES or it is a Double K.O. 😮💨