It was a no win situation ... If he stays quiet and the new investigation shows something bad but it didn't come out till suet the election then he's screwed .... If he brings it out into the open now he's screwed ... seriously. .. What would you have done in his place?
If we imagine an alternative Universe where the American political system ISN'T so polarized that every transgression by THEM is the equivalent of pitching live babies into active volcanoes and every transgression by US merits a shoulder shrug, Comey would be just doing his job in reporting to Congress about the new investigation.
Alas, we don't live in such a world. The new investigation COULD produce anything from severely damning evidence against HRC to "nothing to see here" and, in Hyperpartisanland, everyon feels free to project their worst suspicions about The Other upon Comey's actions.
Yes, he can be fired. The law limits the term he can serve, but does not prevent the president from firing him, just as Clinton fired Sessions in 1993.
Benedict Arnold 