The passport makes total sense if you look at the international tour dates
Everyone is hyper focusing on the text messages where she threatened his career, but I think there’s a much bigger logistical catalyst that forced his hand if you look at the DA's timeline.
He had an album release party on April 24th and was gearing up for a massive international tour in July. We also know her passport was found dumped on the side of the road.
What if she didn’t just show up to hide out? What if she fully expected to go on that international tour with him? You can hide a 14 year old in a Hollywood Hills mansion for a few weeks, but there is absolutely zero chance you can traffic a missing minor through international customs and border patrol without triggering a massive federal incident.
I think he realized his two worlds were violently colliding. She showed up with her passport ready, expecting this rockstar girlfriend lifestyle he probably sold her on. He knew he couldn't actually take her out of the country, he couldn't send her back without her exposing him, and his album release was literally the next night.
It wasn't just a sudden panic. The tour created a hard deadline, and he realized he was trapped by his own lies.
EDIT: After reading through the discussion, the fact that she had already traveled with him to London and France previously actually makes the tension here make even more sense. If she had already tasted that international rockstar lifestyle with him on past dates, she wasn't just daydreaming or naive about how international travel worked, she knew exactly what it felt like to live that lifestyle with him and fully expected to be a part of it again.
So when his April album launch happens and she realizes she is officially being pushed out, hidden away, or replaced on his upcoming summer tour roster, the sense of betrayal hits ten times harder.
This completely answers the timeline objections about the tour not starting until July. It was never about her trying to board a flight with a passport card that exact night in April. It’s about the massive emotional confrontation of discovering she was being cut out of his future right as his career was peaking. She left the house with travel documents on her because their history and his tour promises were physically part of the fight she was bringing to his door. The exposure threat is the legal motive, but the tour timeline is the exact situational pressure cooker that caused it to explode that specific night.
(Final thoughts, I'm not an expert)