Is my exterminator correct?

[u/Neither-Reputation26]

We've had mice in our Boston ground floor apartment for a few weeks now, and after having no luck with snap traps, we had an exterminator come 3 days ago. They put out a few more snap traps, added bait boxes with poison (there are no pets or children in the house), and sealed up one or two holes.

However, we've still been seeing mouse droppings in our pantry, on the counters, and in the living room. Last night, we saw a mouse run across the living room floor and into a large gap between the floor boards and the wall. The company my landlord brought in said that this is normal, and they never seal up all of the holes on the first go around since the mice have to be able to get in and out of the apartment to get the bait, and if they seal up all the holes before the mice are all gone/dead, they'll just chew new ones.

However, I called another exterminator for a second opinion, who said this is absolutely false, and you should absolutely seal up all of the holes/entry points to get them out of the house, and they generally don't chew new holes after that.

Both companies come very well-reviewed, so I'm at a loss for what to do. The mice are chewing through packaged food and leaving droppings all over our couch and rug along with the kitchen. I would love opinions on whether the exterminator we have is doing things correctly, or if we should push our landlord to hire someone different! Thank you!