There are rumors Hillary may have serious enough health issues to force her to step down.
Those rumors have been around for a long time, though.
"Health reasons" would certainly be a face-saving way for her to drop out, and one could certainly imagine that the political deal would be to choose between that and an indictment.
But suppose she refuses, according to the old the Clinton strategy from back in the Monica Lewinksi days: "we'll just have to win, then."
The political calculus then would be based on whether it's less damaging to Democrats to suppress the indictment and deal with the leaks that follow; or to let it go through and find a different candidate.
The decision is not necessarily a slam-dunk, but given that the Democrat alternative at this point pretty has to be Bernie Sanders, and given also that the media will still cover for Hillary regardless.... my money would be on suppressing the indictment.
But maybe her health really is that bad....?