The thing is, in these last days things are relatively quiet, so this will make A LOT of noise and dominate the news, regardless of how serious it is. And Trump knows how to do that well.
They need to come out with a very strong response. No hiding, no pretending nothing is happening or some bs excuse otherwise this snowball will keep growing. And if there's anything else on Trump it's now or never. I really doubt this will singlehandedly make her lose the election, but she can kiss goodbye that conformatable lead.