[RWebb]

the exterminator made the ants "feel unwelcome" (in the walls?) so they decided to move inside the house

are they carpenter ants? sounds like it; if so, you need to fix the house (replace wooden parts like studs, sills, etc.) and also get rid of any habitat outside the house (old stumps, logs, etc.)

you want to find a bait that they like to eat and will carry back to the nest; there are better things than Boric acid these days

in eusocial insects (ants), the workers are just so many "hands" - killing them merely cuts off a few of the hands -- you need to kill the Queen

now go watch Alien and dream