I don't think Seska had anything to do with ending of Worst Case scenario (Voyager S3E25).

I think this episode is part one of the holonovel followed by the second part during the second half. The only break we take from seeing the holonovel be played is when they tell captain Janeway (where she implies that she has to be made to look good) about the first half and when Tom and Tuvok are in the mess hall being hassled by everyone who wants to help write the second half.

Tom and Tuvok write the ending off screen (there is dialog where they argue about a logical ending or a wild twist). The Twist is that part two picks up with the player of the novel meeting Tuvok in the hallway to go to the holodeck to help write the ending. When the player gets there they then get attacked by Seska and get to help rescue Voyager while novel character Janeway helps save the day by brilliantly editing the simulation (in a holonovel simulation).