I question the validity of your statement of "350 mass shootings". That sounds like a Bloomberg "Everyman" created statistic that defines "mass" as 2 or more and includes street crime. The Washington Post did a review and found that the largest number attributable to "mass shootings" was either 61 or 78, with the definition of "mass" as 4 people. Regardless, your chances of being hit by lightning are nearly 8 times more (1 person per 12k) than being part of one of these "mass shootings" (4 people in 100k). The US is not "a dangerous country" compared to any in South America, Africa, the Middle East, and some of the former USSR countries.
With the joke that is Disney "security", it's only a matter of time before some mentally deranged individual shoots up the MK. While the metal detectors are a step in the right direction, the perception of security is more than the reality. Did you see the video where the teenager got into the park by sitting in a baby carriage, avoiding having to pay for a ticket?