Unfortunately the electronics shop in the physics department has been optimized out of existence. MidState, Radioshack are also gone.
6K is not a standard value for gumball carbon resistors. Of course they do exist but only for more (slightly) esoteric 1% tolerance devices. Also more info would be useful power rating, mounting type (through hole, surface mount, size).
Typically Mouser, RS Electronics and TTI are the distributors that get you next day delivery in Texas with UPS ground delivery, most if you order before 8pm. But most get $8 shipping. There are a few around that reach out if they are making an order to consolidate and save a few bucks. Amazon prime might get you an assortment but likely 2 day.
I likely have something but out of town until the weekend. Know lots of others locally that might have some if you need today, my email is in my profile.