What does "bei mir" mean here?

Question

This sentence was found among the subtitles to an episode of Die Chefin:

Sie ist vor drei Tagen bei mir im Club aufgetaucht.

What is difference in meaning with the sentence without the "bei mir"?

Sie ist vor drei Tagen im Club aufgetaucht.

Does it indicate "she was with me", or "while I was there in the club", or that it was "to me that she turned up", or that it was "in my club" that she turned up? The context of the story in which this sentence appears does not assist in distinguishing among these possibilities. Here is another example of this usage from the same story:

Er war bei uns am See.

I think this means, "He was with us at the lake," because the story makes it clear that it is not their lake, in the sense of ownership -- although it still could be a lake they frequently visit. But could this also mean, "He was at our lake," if the context allowed? Here is another one in a different episode (the same writer):

Er ist neu bei uns im Team.

Answer 1

1. "Sie ist vor drei Tagen bei mir im Club aufgetaucht."
2. "Sie ist vor drei Tagen im Club aufgetaucht."

Sentence 1 implies that it is the speaker's club. Either he owns it or he frequently resides there. In both cases it is most likely implied that it happened at a moment where the speaker was present at the club.

In sentence 2 the speaker does not express any relation with the club. It might be a club he has just heard of.

Answer 2

Auftauchen means show up, so we can safely exclude, that she was with me.

While I was in the club is possible, but if this is the only cause, it would likely be phrased

Ich habe sie vor drei Tagen im Club getroffen.

It could possibly be club of the speaking person, but for use of that phrase it would be sufficient, that the person has a special relation to the club. Either being frequently there or working there (in addition to being there in the moment of appearance).

With more context a more precise explanation may be achieved, but as given bei mir can mean a few things.