Here is why:
One: He is forcing the cloture vote on this to be next week, there is not time (its complicated) for the cloture vote to happen before the NSA must shut down the program.
Other business, like the pending trade agreement will have to be dealt with to come back to the NSA.
So for at least one weekend, there will be no NSA spying, and they will have to get it back on line if and when it is reauthorized. Inertia is our friend, if it is down, there will be pressure to keep it down.
Two: He also prevented it from passing cloture by unanimous consent, which is really silence. The chair asks a variation of "Without objection, so ordered" and if everyone is silent, it passes. There are no up/down votes, so no up/down vote is recorded
Now people are going to vote yea or nay, and THAT will be on the record for the next election.