special zealot luck i had from 3 weeks ago. can someone tell me the probability of this? a friend said the chance of getting a 7 kill eye is 0.00396825396%

Ok so everyone is out here looking like 3rs graders at math. First of all when we talk of rhis kind of statistic their is something big that we need to adress. The chance of getting a 7 kill eye is 7/420. So then how do people come up with these crazy numbers. They make 1/420 x 1/420. This is more like calculating the chance of calling 2 special zealots in a row before getting the first one. But most of the time we count kills after getting an eye. So the chance of getting a second eye after a kill is still 1/420. If we don’t care about if we get it on the 7th but look at the 1st to 7 then the chance is just 7/420 or 1/60 or 0.017% still low but nowhere near the one in a billion

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