Getting tickets to Macchu Picchu in person/last minute

I'm doing a trip to Chile and last minute deciding to travel around other parts of South America after.

I'm thinking of doing Macchu Picchu. Obviously tickets sell out months in advance but I read about getting tickets at 6am by standing on line in person at the office in Aguas Calientes

How does this work? If I just show up early enough (like 4am?) am I more or less gauranteed a ticket?

Someone in this thread suggested thres a way to skip the early morning line but I don't really understand how that works or everyone would do it: https://www.reddit.com/r/travel/comments/1reql3z/comment/o7gvfnr/