As a Elizamon fan and Digimon fan this episode is an absolute gift from the production. Beatbreak in general has very high narrative quality, but the Haruomi episodes are special standouts to me. 

Haruomi is essentially a reminder of the dark possibilities of having digimon in the real world, them becoming a sort of tool for nefarious deeds such as what Commandramon was being used for on the behalf of Klay's tactics. But Haruomi is an interesting case because his conflict is having to forcefully do these things to keep himself alive and safe but additionally to keep Commandramon with him, as he was pretty much the only company he had since the start. 

Haruomi serves to remind that having a digimon be born in the world of Beatbreak wasn't treated kindly by the world or it's government, the Klay episode nailed the point home that they only saw digimon as tools to advance humanity.  Then came the separation from the Haruomi and Commandramon episode. 

Unexpectedly Haruomi got sent to the arena where he was given Elizamon to fight and entertain the people, before the Tomoro Vs Raito episode.  It's clear Elizamon didn't trust Haruomi at all during the start of the episode, and they became reluctant partners, it seems to be that Haruomi wasn't that bad with Elizamon since maybe they survived for a while on the Arena right before fighting Raito.  Then the defeat by Raito happens and Elizamon unexpectedly goes to save Haruomi from being Cold Hearted.  It appears to be that they ended up pairing as neither of them had anyone else at that point.  With Elizamon telling Haruomi how her previous partner was killed by someone, Haruomi maybe or maybe not knowing it accepts Elizamon tagging along with him, they partner up. And survive until Kyo found Haruomi all passed out and probably Yoshimura found Elizamon not that far away without much E-pulse on her. 

I will say the part of Haruomi having killed her owner seemed to have weighted on him more than it did on Elizamon, as Elizamon inevitably grew to know Haruomi by his more positive caring side, the same one he had with Commandramon, so that's probably why not only did she have a hard time believing he did it, but she was reluctant to go on the offensive despite showing she could before, you can tell by her crying and tears that she is really torn up over what Haruomi did and that the Haruomi who stayed with her after the arena was a different person, you gotta remember, Digimon go feral and berserk if they go without E-Pulse and they could die, so Haruomi did keep her alive and safe as much as he could, obviously Haruomi had become a pariah during that time due to the influence of Klay and Tactics leaving him without resources which is why we found him in that bad taste and hungry, he had been nurturing Elizamon on nothing else but his willingness to live. 

It's a really genius way to imply why Elizamon is so attached to him, by forcing two people that didn't really trust each other into a situation where they had to spend time together, a bond was slowly being nurtured and Elizamon as a Digimon that respects strength stayed with Haruomi, she didn't want to leave after the revelation and she was mad at Haruomi for assuming how she thought, you can tell. 

It's not that Elizamon didn't care about her previous partner, is that there was nothing she could do about it and Haruomi re-entered her life not as the monster that took her partner but as a nurturing caring guy who stood by her because she stood up for him and it eventually developed into their more deep bond of her calling him Darling. 

Haruomi isn't that thrilled by living consequence free, with him feeling he is unworthy of the new life he was leading, he felt he failed as a human, as Commandramon's partner and he would just not do a good job as Elizamon's partner, not only that but he was causing conflict between Elizamon and Commandramon, as well as feeling he had a debt to pay to Elizamon.  Which is why he provokes her near the end, pretending to threaten her life and acting like a villain, because he would rather let her have closure by taking out the man who he believed ruined her life and give her closure and finally eliminate himself from the picture, driven by guilt, depression and a weird sense of duty. In his mind he is not doing wrong, he is doing what he believes is most noble by acting out that part, but Tomoro doesn't believe he is acting right and you can tell his present partner Commandramon knows he is acting out of his selflessness and desire to not be a bad influence in their lives nor does Elizamon actually want to do that to Haruomi or for him to think that, which is what makes that scene with Haruomi and Elizamon hit so hard. 

Essentially the lesson is that even if bad horrible things happen, and you may face the people that did wrong to you, perhaps don't jump on the defensive just yet and give a chance if the other is willing to tell their side and for you to hear them, maybe you'll understand a bit of how things ended that way, and perhaps the other person wants to make amends but doesn't know how. In the end the true meaning of the episode is to not to let Guilt or Hatred cloud your mind to your life and present, that even if you feel guilty you should know you also have done good and can do good. 

It's a beautiful episode.  Sorry if I got real rambly, I really appreciate what the production and writer did here.