One possible answer to your "real question": I want to disclaim that this is pure speculation. I have no insider knowledge or indeed any particular familiarit

One possible answer to your "real question": I want to disclaim that this is pure speculation. I have no insider knowledge or indeed any particular familiarity with the institutions in question. The FBI may want this authority and this precedent and think that this is a good chance to get it. They may say, "Well, the San Bernadino case is a high-profile case that may sway people, including judges, who would otherwise be less inclined to back our request. Who knows when the next nationally-publicized case will be in which the likely perpetrator carries an iPhone?" They may also believe that the current political climate is good for their case. And they probably also believe that there's no harm in trying. If the courts rule against them, they haven't lost anything. If the courts rule for them, they get a brand new tool.