Ren's mouth twitches with distaste when he hears the source of the fake saber. It's... ultimately not that surprising that they'd want to replicate one, but to do it in such a way is absolutely an insult that he doesn't exactly appreciate.

A part of him would like to show them a thing or two about what a lightsaber really is, and how it's not just a toy... but helping Regnard modify it to work properly?

"You want me to help you build a lightsaber."