Open door or not still..
First .. mass shootings defined as:
FOUR or more shot and killed in a single event [incident], at the same general time and location, not including the shooter," differentiating between mass shooting .

Found discrepancies in the odds of being in a mass shooting or killed in a mass shooting I should say , anywhere from one in 4 million to one and 100 million.. in the US
This was in the US. Also the odds of being struck by lightning in the US is 1 in 500,000...