Red is for safety. (Mauve is the universally recognised colour for danger.)
I thought danger was teal?
Red Dwarf Ping!
HOLLY: (Appearing on the screen) Purple alert, purple alert!
LISTER: What's a purple alert?
HOLLY: Well, it's sort of like, not as bad as a red alert, but a bit worse than a blue alert. Kind of like a mauve alert, don't want to say "mauve alert."
RIMMER: Holly! Wipe the rabid foam from your chin and start again.
HOLLY: There's some sort of disruption to the time-fabric continuum. At least, I presume that's what it is, it's certainly got all the signs. There's this big wibbly-wobbly swirly thing that's headed straight towards us.