Did I run into a RMT? A Very Odd AK Run

So I get into a party via roulette as SCH. When we go in I meet the Paladin and we see two black mages in the party. The boss music is already playing so I figured I guess I did a join in progress.

We run to the first boss, the entire floor is clear, my screen starts lighting up with mob deaths. The black mages aren't talking, and me and the Paladin went and just opened the chests..all the mobs were gone. Eventually they both left.

We got in two others and took out the first boss..second floor for wall, completely clear..third floor was missing mobs too.

I mentioned it to my FC and people acted like it was a common thing or not a big deal. What did I witness in there? Is this something common for people see?

If they cleared mobs without even killing the gate bosses then obviously there's something wrong. Hacking through floors or something? Idk.
But we all know, you can't access the next part of the dungeon if you don't beat the boss that's blocking it.
Probably because they assume AK is old , thus thinking GMs etc will be more lenient on watching for that stuff.

If you see this happen, report the people you cant see to GMs. This is how bots run dungeons.

Sounds like RMT to me. They pos hack/teleport around the dungeon aoeing mobs for the gil drops and somehow get themselves above the ground so mobs cant touch them. Report anyone you see doing this.