Both the short stories and essays were equally interesting in their own way.
After getting fired, it appeared that Carter tried making a new transponder, but he told Vrataski it didn't work, possibly because of his lack of resources following his demotion or because he didn't have a subject with a link to the Alphas to test it on.
After the act, a rippling wave emerges from Louvre, and we see several mimics dead on the streets.