It’s clearly stated, that they were on the siding track by someone’s mistake. She asked them to drive slowly in case of something and if another one is green, than go back to main road.

She knows how trainroads work and how to solve problems. She found a problem and solved it. She asked them to drive cautiously, so I don’t see a problem here.

Is it wrong for you to drive on a red light, if it’s by mistake of someone? You would also cautiously drive through it, to get to your destination, aren’t you? Maybe you would take another route. We take into account, that you know by fact, that this red light is broken and you wouldn’t wait until it’s fixed in front of it.

For me it’s not wrong to break this rule in the context of the situation. They were caught by mistake and it made a problem of getting late. She understood the situation, thought it through and solved the problem. It wasn’t reckless, which is clearly stated by asking them to drive cautiously.