AOC2024 Day 6 Clarification

[apw024]

Hey @jonathanpaulson thanks so much for posting your solutions to this year's Advent of Code. I especially liked your topological sorting solution from Day 5.

I'm just wondering about Day 6 and why is it that you loop over all of the map's cells and, each time, repeat the simulation process from the guard's starting point. I believe this is crucial to my understanding of part 2 of that day. Would appreciate your response.