I think more so when Picard exits the Nexus. When he appeared back in reality.
He could have "arrived" on the planet prior to Soren aboard the bird of prey, disabled/destroyed the missile at his leisure. This also would have (unbeknownst to Picard) saved Kirk's life.
Arrived aboard the Enterprise as Soren beamed over from the observatory, had a security team escort Soren to sickbay, then the brig.
Arrived back prior to the time of the fire that killed his brother and nephew, communicated to preventing their deaths and
prevented the Romulan attack upon the observatory saving the life's there and
prevented the destruction of that star (and the observatory) and
captured Soren too.
having Picard walk into Ten-Forward and arrest Soran would have made a boring end to the movie. It's "rule of drama" people. Why didn't the Borg in FC travel back in time while in the Delta Quadrant and THEN try to assimilate Earth when there'd be no advanced opposition?
And yet somehow, fans forgive FC for that, yet they endlessly harp on GEN for doing the same thing.
I have no problem with letting it slide for both movies. My problem with GEN is that the whole nexus thing was horribly contrived to get Picard to meet Kirk and get his help to fight Soran. (all of this because they didn't want to do a time travel plot, which they ended doing in the very next movie
It wasn't even epic. It was 3 old guys fighting. The whole scene reminded me of The Simpsons when Nelson is picking on Bart because Homer won't give Mr. Burns his teddy bear back, so Mr. Burns stops all the beer imports into the city:
Nelson: My old man can't get a beer because his old man won't give a bear to another old man! Let's get him!
Jimbo: Wait, why are we getting him?
Martin: Look, fellows. The first snapdragon of the season.
Nelson: Nevermind. Let's get him!