<s>[INST] I'm in a situation where I need to update a value in a MongoDB collection based on a replacement pattern matching a specific case-insensitive string pattern. I can use the `$regex` operator.

The pattern can contain regular expression special characters, so it needs to be properly escaped. I want to test this with a simple example. 

Please show me how to create a dummy collection, insert some records, and update those records based on a replacement pattern using `$regex` in MongoDB for this case-insensitive match. 

If you can, provide an example with escaping special characters and then using them in a replacement string. 

I'm using MongoDB version 4.4. 

First, let's create a collection with some sample data:
```javascript
// Create the collection if it does not exist
db.createCollection("dummyCollection");

// Insert some data
db.dummyCollection.insertMany([
    {name: "John", email: "john.doe@example.com"},
    {name: "Jane", email: "jane.doe@example.com"},
    {name: "Jim", email: "jim.bond@example.com"},
    {name: "James", email: "james.jarvis@example.com"}
]);
```
Now I want to update the records that contain "doe" (case-insensitive) in the `email` field with, say, "smith". The `.*` and the pattern itself should be properly escaped.

How can I do this in MongoDB?[/INST]