This is an inadvertant whistle. It's an easy mistake to make an most officials will say to themselves when a field goal is being lined up that it's a live ball if blocked. I don't know of any official who considers risk minimization while a play is live.
That said, if an inadvertant whistle ends any down in which there is a live ball foul that is accepted (as this one is) the whistle is ignored and the penalty is enforced. So even though there was an inadvertant whistle on this play, it didn't matter. Officials should have marked the ball half the distance to the goal from the original line of scrimmage and marked it as first down. If the 1 second was left when the whistle killed the play then there is 1 second let. If there was 1 second left when the play started and the clock expired, then there will be 1 untimed down.
If you'll indulge me a brief story. Big game. Close late, Lots of tension. Team A punts high and not very deep. Return man signals for a fair catch. Kicking team member in coverage gets in the way and bumps receiver. Back judge flags it just as the ball comes down and goes straight through the receivers arms and bounces off his knee. There is a mad scramble for the ball and the back judge (an excellent official) has a moment of panic-confusion because of the strnage play and he blows his whistle while the ball is loose, just before its recovered by the kicking team. They start celebrating and he just dies a thousand deaths. He comes up to me with this crestfallen look and apologizes for screwing up that play so bad with an IW. Another deep official comes in and says there's a flag for kick catch interference. (As a referee, I never get to see these things. I rely on being told about the important action downfield.) I ask the back judge: "You had a flag?"
Yes, he said, KCI on the kicking team No 14.
"OK then, none of the rest of that stuff makes any difference at all. Enforce the penalty, rekick and go on with the game.