Analysis on the "ache" comic.
In the beginning, Mizi is confiding to Sua about her problems back at home. We have no idea whether the injury Mizi has on her face is a) self-inflicted, or b) caused by someone—most likely her mother.
The panels below show Mizi asking if she could stay at Sua's place for the time being. We can tell that Mizi feels a bit embarrassed, as she reassures Sua that she'd pay her back.
"...so please..." also indicates how desperate Mizi is at the moment. I do believe she grew up in an abusive household due to her determination of wanting to escape from her home, so she seeks help from her closest companian, which in this case, is Sua.
Sua then immediately reaches for Mizi's hand. You can tell how much Sua truly adores her by her lovesick gaze and blush.
"Just knowing that you're relying on me is enough..." implies Sua's unhealthy codependence upon Mizi. This is why Sua's personality is so empty without Mizi. Sua revolves her entire personality around Mizi, because without Mizi, her life is blank. In her perspective, as long as Mizi is by her side, she is perfectly content.
"You can rely on me as much as you want... I'm just happy I can help you..." further displays Sua's unhealthy attachment towards Mizi. She is so obsessed with Mizi that she'd do anything to keep Mizi in her arms.
Mizi snaps a bit in response, disbelieved and even disturbed by Sua's immediate agreement. She despises the idea of being a "begger" towards Sua.
Contradictory to Sua, Mizi seems to dislike the idea of appearing overly attached or dependent on someone, which isn't too much of a surprise. Out of the ALNST/ZOMST main characters, Mizi is definitely one of the most evident ones who is afraid of being seen at her most vulnerable.
"Someone as kind as you is being so hard on yourself." This is how Sua views Mizi. A person who can do no wrong.
Her toxic and unhealthy codependency is further revealed in the panels below. She objectifies Mizi, viewing her as this idealistic angel or goddess. Sua quite literally worships Mizi's image.
Her idealization of Mizi is part of the reason why she is so obsessed with her. It's common for humans to attach to people or objects that seem perfect and picturesque in their eyes, which is what Sua is doing in this case.
Sua's emotional manipulation can further be seen in the bottom panels. Since it is blatant that Sua is incredibly obsessed over Mizi, what do people normally seek from their obsession? Control and security over the recipient.
"You really don't know yourself at all. Don't be like that..." implies Sua trying to have control over Mizi's upsetting thoughts, as well as the need to keep Mizi safe within her arms.
Sua seems to believe that she knows everything about Mizi and is the only one who can truly understand her. Although Sua does care deeply for Mizi, it is shown in a way where she completely ignores Mizi's flaws.
As expected, Mizi lashes out even more harshly. She hates the idea of appearing like a pet towards Sua, as it not only strips her of her own composure, but also reveals her ugliest vulnerabilities.
Then, Sua barges in by saying to "just hit her." This is symbolic of her own self-destructive nature, where she will do anything that remotely satifies Mizi, even it is at the cost of her own health. Sua loves Mizi more than she loves herself (yes, this is a HYULUKA ref).
"If I can prove it to you... Then maybe that'll be enough" proves how far Sua will cross the lines to keep Mizi happy.
Sua wants everything to do with Mizi, even her most ugliest characteristics. She craves this connection with Mizi, so much that she would be willing to endure any pain just to feel closer to her. Sua's willingness to get hit and infected later on is such a beautiful symbol of how she views her relationship with Mizi.
Even if there is pain or agony, Sua is content to experiencing it as long as she is experiencing it with Mizi.