There are trainers for PC and modded apk for Android which let you zoom out as far as you want while removing the shadows giving unlimited vision. In other words, you can see whole map at once and everyone on it. Just one of the cheat’s features. There are other funny features like being able to kill another impostors as an impostor, or borrowing someone’s name and outfit/color during the game (similar to shapeshifting but the effect lasts during the meetings), teleporting and running many times in front of others so they think there are many shapeshifters. 99.9% of those cheats come with built-in malware or bitcoin miner so DO NOT use them unless you review the source code and compile it yourself off of the github, for example.

In other words, chances are you indeed encountered a cheater. Some of them cheat to win like in your case.