The Ruger carbine doesn’t really give you much more than what you’ve already got with your handgun. IMHO it makes sense only if your agency prohibits full power rifle cartridges such as the .223, which is not your case.
It is increasingly being accepted that a .233 will penetrate some structures less than a handgun round. This is backed up by quite a bit of testing. (I personally have some qualms about this. But, my concerns notwithstanding, there are plenty of credible sources concluding that this is true.)
However, a .223 does have greater range than a handgun round. This is great if you need the range, but a liability if you let a round go wild in a populated area.
If you feel strongly that you need an alternative to the Mini-14, I’d suggest a shotgun, assuming that option is open to you.
Keep in mind, though, that having two different long arms with different controls can result in mistakes in the ‘fog of battle” – like, for example, trying to pump a Mini-14. If you go with two long arms, try to match up the operation as much as possible.
My suggestion would be to simply stay with the Mini-14 and make sure you hit whatever you shoot at. Human bodies make great backstops, esp. with a .223.