I've never had a chipmunk in the office... but I did once have a squirrel in my attic sewing room.
So I got Shelly, my most efficent huntress-cat. It took her less than five minutes to catch the squirrel, by the nape of the neck, same way mama cat carries her kittens.
I suppose it did look rather strange to see me hanging cat+squirrel out the open third floor window, shaking them both to make Shelly let go of her "prize".
Prize squirrel was unharmed, and ran off through the gutter.