I still make mistakes a lot, and even when I check everywhere, I often can't spot any anomalies. I can notice some things, like trash on the ground, but there’s still a lot I’m missing.
One thing that would really help is if swiping my pass at the turnstile reader acted as a check: if I made a mistake, the game would notify me right then, reset the loop counter, and close the train doors so I can't enter. That way, I'd know immediately that I got it wrong and could try to figure out what anomaly I missed.
Lastly, I’d also love it if the flashlight were brighter and had a longer range.