Technically that would result in a "grey". Not your classic grey but a tertiary grey.
Broken yellows depending on the pigments will go brownish, if the purple skews it too far to grey add a bit of burnt sienna or orange. You are going to get something interesting when you play with it, and when ever i mix paint too much…I WILL get to muddy brown at some point no matter where i started!
My basic approach to painting is never use pure tones, or anything straight out of a bottle, even if it’s a broken hue. I strive for subtle individuality and variation in hue on every figure, even if it’s a freshly uniformed guard unit straight out of the supply depot.
A wet palette is my favourite tool.