I don't think Comey is necessarily hiding in order to cover for Trump. I think he is probably not going to let them in on the big stuff out of danger of it leaking until they are ready to drop the hammer. I don't think they have three investigations going on at the same time for no reason.
In fact, to digress a bit, I don't think he was partisan during the campaign either despite democrats feeling differently. There was reports, that seem to have fallen to the way side, that there was a contingent in the FBI that was anti-clinton, in NY if I remember correctly, who were found to be leaking stuff to Giuliani. Giuliani was the idiot who told bretbear (sp?) on fox that a "prosecution was imminent". There was a story around that time that said he was feeling pressure by the leaking of agents below him and from congress from people like Chaffitz that were intent on making sure all and any information is released as soon as possible, obviously for partisan reasons.
In that case, he probably was very "open" out of fear of being accused of being partisan and protecting Hillary.
I think democrats are in danger of maybe stepping too far over the line and not allowing for a full investigation to complete before demanding the release of the most damning information.
I and I think democrats should wait for the whole pile of shyt to start flooding so stuff isn't forgotten over time before people start resigning en masse and possible ending up in jail.