Dear Federic@,
Here in the north of England, if we say: "I īm going to X īs", (using an apostrophe ī), it refers to going to a house, a building, a place, which is well-known to both the Speaker and the Listener.
"Let īs go to Maria īs" ( = "Let us go to the house of our mutual friend, Maria").
"Let īs go to Dad īs" ( = "Let us go to the house of our father").
"Let īs go to Robert īs" ( = "Let us go to the house of our brother, Robert, who we have recently been discussing").
"Let īs go to the Doctor īs" ( = "Let us go to the surgery of the Doctor, and we both know which Doctor I mean").
"Let īs go to the Chemist īs" ( = "Let us go to the Pharmacy of the Chemist which I always use").
"Let īs go to the Newsagent īs" ( = "Let us go to the Shop of the Newsagent where I/we always buy our newspaper, or the Newsagent īs shop that we have recently been discussing").
Using this analogy:
"Let īs go to the Teacher īs" ( = "Let us go to the house/residence/classroom/private room/study of the Teacher who we all know and who we visit regularly").
This may be what is intended in the script.
Les Douglas