Unassisted Tower Ascent Easter Egg?

[some_dead_guy]

So I've been looking at a few videos showing some impressive techniques to ascend the final tower without the help of any Messengers, but what intrigues me the most is the Terminal-head hologram-bot that often shows up when you reach the highest level. This bot is largely disregarded and unmentioned in videos, so I'm interested to know what determines its appearance and behavior, which appears to vary. Here are some examples:

(Center of top floor) https://youtu.be/0SpssxKz63I?t=233
(Peering over side) https://youtu.be/DsNQqbyHuow?t=240
(No Appearance) https://youtu.be/UfxIQZ76vh4?t=163

Indeed, when I utilized these techniques to try a solo ascent of my own, the bot never appeared. If anyone has some more info on this mysterious easter egg, it would certainly help satiate my curiosity.

[apple1417]

He spawns when you reach the final level without Shepherd leaving his cell. Shepherd needs to have spawned for this to happen, otherwise there'll be a scripting error - by jumping around the purple in the last video none of the bots spawn (and the storm doesn't start).

Tome himself has super simple logic:
1. He spawns and walks forwards
2. He waits for you to get close enough
3. He walks to the switch
4. He waits for the elevator barrier to close
5. He walks over to the edge
6. He waits for you to get close enough again
7. He despawns

There are also a few extra animations and delays in there but that's the gist of it. He always does all of this, the videos you've found just don't hit the triggers or leave while he's moving.

[Emoon]

In addition to that, it seems TIME is also an important factor. If you take to long to reach the top floor, you end up not finding Tome at all.

As proof, I tried the exact same route, at first going fast and then later taking my sweet time. He showed up only on the former attempt.