As alluded to in the title, I believe Reid was teaching amnesiac Subaru to think for himself in Ep. 77 since this version of Subaru was really used to having everything explained to him, much like how he’d get an explanation on everything after he’d initially lost his memories and immediately after the first time he fell to his death.
More on this front is that I also believe Reid saying, “Ah, finally.” is him potentially following Echidna’s instruction in waiting for a specific cue before going after Julius, which was that rumbling he heard, which may have been what prompted him saying that.
Of course, maybe this is just White Fox being lazy on details, but while the first part of the GIF has Reid saying that Subaru came too early in Ep. 74 may imply he’s aware of the passage of time, in all the instances Reid had screen time, there was zero indication of in which direction the sun was shining, and given how heavily Re:Zero focuses on details and how the area in the second exam may be a special sort of space like Echidna’s Dream Castle, Reid shouldn’t be able to perceive how much time had passed as getting exposure to sunlight is important in ensuring one has a normal circadian rhythm, and this space possibly has no sunlight but merely mimics daytime conditions, so even this Reid who apparently only remembers having swung a sword for 3 months may be on the same side as Satella, Echidna, and Flügel and is acting with future knowledge from Echidna through a soul link, contract, or oath with the assistance of her Authority of Greed: Tome of Wisdom.
More to potentially back this up is that Reid basically said that amnesiac Subaru shouldn’t have ran and instead hashed things out with his people in the second and third parts of the GIF, which is very generous advice for someone who’s supposed to be an enemy, almost as if he’s guiding him in his own way, and this is especially notable since Reid is supposed to be someone who loves bullying the weak, so why did Reid seemingly give him any advice when the interaction could’ve been much shorter and even harsher (Yes, I know piercing his body was harsh)?
The words Reid said in the second and third cuts of the GIF may have been meant to highlight just how strange it was that amnesiac Subaru went to a higher floor, and particularly to him, even though amnesiac Subaru was told that the group was more interested in going to the higher floors ’cause they wanted to find out what happened to him and pass the exams so that they could leave, which suggests something’s up.
Thus, I conclude Reid may have told amnesiac Subaru that he’s early ’cause he knew that the poor guy wasn’t really ready and was in no condition to face him. Yes, Reid’s the type who likes to bully the weak as Shaula had said, but I suspect there was more to this interaction than what was on the surface.
I strongly believe the Freud reference in Episode 69 was meant to show that Subaru’s the type to act on hunches and subconscious thoughts given what Freud is known for (and yes, I as told that in the WN it was a Kurapika reference and was a different reference in the LN, but the point still stands given an extra loop was cut off in this episode according to LN viewers as the Freud reference makes great sense in the anime given Subaru chose the path on the right). That’d be why Subaru chose the path on the right, ’cause it led to Satella’s sealed body as shown by the ever increasing amounts of miasma, and Satella herself had asked Subaru to love himself and then someday come kill her in Episode 38, which could be indicative of a lovers’ promise to kill her four hundred years ago, which Subaru subconsciously tried to fulfill or fought against fulfilling (either could work).
Where I’m going with this is that I’ve extrapolated the Freud content from Subaru in Ep. 69 to Ep. 70 to show that Subaru wasn’t crazy or stupid to think he had Returned By Death at the start of the episode when he woke up on Emilia’s lap given he woke up in a new place, and it was ’cause he subconsciously realized that he’d been to the dark world where Satella lies within the vicinity of his soul, and since most visits to this dark world involve him dying, he instinctively thought that he’d died, not ’cause he has no brain or is a super irrational person, but ’cause he subconsciously linked dying with going to the dark world.
As such, I theorize Subaru thinking of Reid in Ep. 70 despite it having been explained earlier in the episode that Reid died of old age is also ’cause subconsciously he knows what’s in the tower much like he knew the path to the right in the cave/tunnel led to Satella, and he knows there’s a version of Reid on one of the higher floors due to his time in the world 400 hundred years ago, and that’s why Subaru thought about Reid in the moment Shaula said she gives no thought to who she’s killed, not ’cause he can’t remember basic details, but since he’s letting his subconscious thoughts and hunches drive him.
That’d be part of the reason why amnesiac Subaru asked Reid any questions at all in Ep. 77 despite his last memory of him being how he pierced his body and inflicted so much pain to him, ’cause Flügel, Volcanica, and Reid were part of the Hero’s party, and Reid was most likely his friend 400 years ago, and amnesiac Subaru felt an affinity with him despite the pain he made him suffer through him. For more on why amnesiac Subaru could have any subconscious memories of Reid at all despite likely having his memories eaten by the Authority of Gluttony due to the line in Ep. 74, “Memories are what shape a person.” from Rui Arneb’s VA, read this: https://thoroughwatch.org/?p=281
Thus, I believe that Reid may have given Subaru a very teachable moment that he’ll need to draw upon by thinking for himself instead of having everything answered for him, which will be crucial for dealing with the issues of this arc. And given Reid’s words in Ep. 74 basically stated what amnesiac Subaru had to do, which is not avoid his friends and face them honestly, which is what he resolved to do in Ep. 77, I’m leaning to Reid perhaps having intentionally given him a leg up this episode.
Reid doesn’t necessarily need to be a nice guy. This version of Reid and perhaps even the original may have been in on the plan of the original Echidna to save the world, which Tea Party Echidna herself may have been following.
As for Reid not recognizing Emilia’s appearance or Shaula’s, this could possibly be explained by this Reid being an artificial construct of the Pleiades Watchtower, which was hinted at in this episode given it was implied that since the tower was under attack that he no longer had to stay on the second floor. Thus, this Reid may have partially formed due to a Book of the Dead, specifically Reid’s, and not its entire contents, with the memories he did have forming the basis of this version of Reid’s soul, and if I’m right about Books of the Dead being partially a by-product of Echidna’s Authority, that may give Echidna some power over this version of Reid.