So Mao-chan holds a grudge and is trying to kill Reiga, after all....

No, I think she's just one of those people who you absolutely, positively cannot leave anywhere near the shiny red buttons.

Yup, definitely don't let that one handle anything critical.

Garrus said:

No, I think she's just one of those people who you absolutely, positively cannot leave anywhere near the shiny red buttons.

She was told touching the horn = disappeared people.she tried to kill Reiga in her sleep. I think she's acting out subconscious impulses.

Garrus said:

No, I think she's just one of those people who you absolutely, positively cannot leave anywhere near the shiny red buttons.

Obviously, you should handle Mao using the Overlord's Checklist mentality - the big shiny red button that says "Self Destruct" will instead cause a jet of water to spray whoever pushes the button. If it is somehow necessary to have a self destruct button, it will instead be a plain button labeled "sewage ventilation".