A minor update, I did email Terro customer service to ask if borax is still active inside the body of a dead ant. I explained my situation but I'm not wholly expecting a useful answer from either an outsourced or minimum wage customer service employee, lol. But it's worth a try.
I also am reading about ant barriers that ant keepers use to prevent escape of their workers. Perhaps I can put them in mine and it would cause the opposite effect so they would not come into my terrarium.