Iruka is a tentacle monster.
Episode 30 clearly shows that he's not what he seems. Sapphie's reaction suggests that under that dolphin costume is something very horrible indeed... And it would explain his year-long lusting after VA-VA-VOOM Jill Konia, which ends in marriage... Oh dear.- Just cause he's a tentacle monster doesn't mean he'd be bad. Or Jill wouldn't be... into that sort of thing.
The scenes in the preview for episode 52 are Ruby's fantasies.
During the Dark Jewel War arc, Ruby is imagining herself and her friends as a Universal-Adaptor Cast in a mafia movie, Gundam, etc., to escape the reality of the situation she actually is in. The scenes we see in the preview are a distillation of her thoughts. Compare to the last two episodes of Neon Genesis Evangelion, especially the "idealized high school life" portion, which are set in Shinji's mind as Third Impact is going on around him (The End).