'Mother Deborah' is the so-called caretaker of the Neko twins.  Her primary job is to ensure that they are conditioned to serve a purpose.

The laboratory would not invest this much time and money into them to have them not perform to the utmost degree. 

Things such as unnecessary emotions and curiosity are to be squelched by her with cold precision. In short- she is the strict punisher. 

Imagine her to sound like what an 50-60 year old traditional nun who runs a strict catholic school might sound like when very angry?