What? That's how you minimize risk because there's a good chance the markets will continue to slide. It's literally why the markets are down - because investors are pulling out and parking their cash in safer havens.
People should have an asset allocation, and stick to it. Right now, people should be re-balancing by selling off their now overweight bond allocation to buy equities. What you're suggesting is counter-productive.
At this point we have likely entered recession or depression territory. The rebound is unlikely to be instantaneous (unless a convenient cure is found) and when things calm down I can put my money back into the market starting from a 10% locked in gain.
For everyone else not near retirement, most are going to be better served by ignoring the volatility and continuing to invest as usual. Time in the market vs timing the market and all of that jazz.
You don't minimize risk by reacting to daily market fluctuations. You minimize risk by choosing an asset allocation that allows you to ignore those fluctuations.