@theseniorsenor isn't katakana meant to be used for foreign loan words? Maybe it is meant to show they're flustered and speaking in a stilted way, but doesn't the slipping into more polite speech show that anyway?
At first I thought the TL was confusing katakana and keigo (polite/formal speech), but it looks like they're actually confusing it with katakoto (stammering/baby talk).