The only way for this to happen is for Grand Duke Konstantin to decide that the benefits outweigh the risks. Had this been so then arguably the whole problem of the Praetorian Guard-esque Imperial guards would never have arisen and thus any scenario that favors Konstantin saying "Yes" has already butterflied most of 18th Century Russia's political history. If he does do a 180-degree turn then Russia's got a Tsar who's in the best case an earlier Alexander II, in the worst case a milder and softer version of Nicholas I.