A rational person would say, if this is a love story and the main romance plot is stalled, I have to solve that problem or give up. But for me, developing ideas is not a completely rational process. I leave the central romance plot and go looking for another problem, in a different area of the story, and hope that the second problem contains the solution to the first.
In Passengers, only one subplot is going on. The ship's operating system is malfunctioning. The problems are minor at first but grow more serious. For a long time, my guy ignores them. This is good because it builds suspense, but bad because it violates character consistency.
I've decided already that my guy is an engineer or mechanic. This is a man who likes to fix machines. But glitches are happening on the ship, the big machine on which his life depends, and he's ignoring them? Implausible. I no longer believe in this character.
This happens to me all the time when I'm writing outlines. The characters just won't do what the plot calls on them to do. When that happens, I have to change either the plot or the character, and I'd prefer to change the plot.
So, I ask myself, can I get rid of the ship malfunctions entirely? No, because this is the reason why my guy wakes up. Okay. Only one other possibility: the malfunctions are happening, and being an engineer, he notices. What follows from that? He realizes the ship is in deteriorating shape. He goes looking for the problem. To me, this is more interesting than his mooning over sleeping beauty. His life is on the line, which gives me the potential for strong, suspenseful scenes. When he does find the problem, he realizes he can't fix it. He needs someone with specialized knowledge. He reads the files and finds out that the person with the expertise to fix it is sleeping beauty, whom he hasn't noticed before. He has to wake her. If he doesn't, she and everybody on the ship will die.
This is an example of how one problem can solve another. Making the character consistent, I've found a way to avoid having him make a decision that goes against the genre. You'll notice it's a very simple solution. The original, problematic way the story went was 1/he wakes sleeping beauty 2/they fall in love 3/the ship malfunctions get steadily worse until 4/they have to fix them. All I've done is change the order: 1/the ship malfunctions get steadily worse 2/he wakes sleeping beauty 3/they have to fix them 4/they fall in love.
Here's another tip: if you solve a problem and feel clever, your solution probably isn't going to work out. If you solve it and feel dumb for not seeing how obvious the solution was, you've probably found the right answer.
I have now turned my initial idea into a bare-bones outline that I would like to write. I'm not saying it's a better story than the movie Passengers, or that I'm smarter than the scriptwriters. I don't doubt that all the possible variances I've set out above occurred to them. They made different choices than I would. Or the producers or stars or studio executives did. (Or the associate producers' girlfriend's hairdresser, who Elmore Leonard tells us is the most influential person in movie production.) That's why I'm glad I'm a novelist and not a screenwriter. Even if the pay isn't as good.