-k option kills process but triggers error message

I'm using concurrently to run react-native start whilst I build my release app and install it on my phone. Using the -k option causes the react-native start to exit when the build finishes, as desired, but it exits with an error code which isn't very visually nice. Is there a way to cause the react-native start process to exit as cleanly as if you had hit ctrl-c?

Many thanks, and great module!