There are circuit breakers in the market if it drops too far too fast. Google market Rule 80B and could add circuit breakers, then read the rules for the shutdown triggers. Some seasoned traders told me about it a couple years ago.
Your 700 points down could have been one of the percent qualifiers.
I don't know why the spokespeople aren't mentioning that instead of a "technical glitch". It could have been a glitch or a hack.
One person (trader) shut down the market a few years back. Google flash crash 2015 for specifics on that.
Maybe they know but are playing it safe because they didn't want a panic. It closed down about 270 which isn't good but not earthshaking.
If it has just been the NYSE..that would have been one thing ut with the addition of the WSJ..lil incident..topped off by the United Airlines incident..I smell intereference.
It would not surprise me terribly if it were discovered that it wasnt the chicoms afteral. Given the state of the markets in China.and the obama regimes love of both crisis and manipulation...ot would surprise me even less if they were involved.