When Ilk gets ill with Drilo's disease, she's put inside a medical capsule with lots of cables, her skin has gone pale and she can barely breath. It's evident that she's suffering. This is heartbreaking for Red, as there's nothing he can do to relieve her pain. Before departing for Sobr, Red goes to check on Ilk one last time, and she reaches out a little hand for him, recognizing him, even calling out.
The loss of Miyuki is clearly still an open wound for Red. Whenever he's sad, he eats one of the cinnamon rolls she made for him before her death as a way to remember her, and he even kept a picture of the two of them in their summer home in Vacatio.
Red is utterly devastated when Ilk's leg is torn. Sure, it grew back, but one can imagine what it must be for a father to witness such a gruesome thing happening to his child
Lost
During a monstrous argument, Red ends up slapping Ilk for the first time ever, and he quickly regrets it when he sees the heartbreak, but especially the fear on her eyes as she looks at him. Before he can apologize, she runs off. Later on, when Ilk is dying due to a branch having gone through her abdomen, Red is reduced to tears as he begs Lena to save her. He'd never forgive himself if the last thing he ever did to his daughter was slapping her and calling her a disappointment.
After the above-mentioned argument, Red ends up snapping at Lena when she tries to calm him down.
Red: MIND YOUR OWN BUSINESS! Stop acting as if you were her mother! You're not and you will never be! She's my daughter and how I raise her it's NOT your problem! Don't forget your place, medical drone!
This is heart-breaking for Lena, especially since they had been bonding the past few days and she thought he considered her a friend.
Later, when Red tries to apologize, Lena coldly rebuffs him and informs him that she'll be asking for a transfer back to Irk when they return despite him pleading her not to leave.
Indokani
Red's well-meant attempts to help Purple pass his tests are interpreted by Purple as Red not trusting him, leading to a huge fight between the two.
Purple having to face the fact that he's been a terrible owner for Cheesecake, having pampered him to the point of ruining him.
Pre-Parental Panic
One of Irk's previous rulers, Tallest Laven, lost his wife and smeet at childbirth. He was so grief-stricken that he banned natural reproduction and killed newborn smeets in their mothers' arms, as he couldn't bear the thought of other people having what he would never have.
