I don't mean to overthink the issue, but I'd imagine that each uniform should be predominantly Red/Yellow/Blue respective of their departments. This is practical in ground STFs, for example, where it'd be handier to be to see at a glance who in your team is tactical, engineering or science. Also, the primary colours are easier to distinguish from the drab dark environments of ground STFs, allowing for better awareness of your team mates. I'd also propose a fourth uniform (Aqua) to distinguish medical from science.