How is “not forgetting” used?

In The Gift (2015), one line is: “Well, you're not forgetting that this guy's not exactly stable?”

Which movie is “not forgetting” from?

The clip at the top of this page is from The Gift (2015).

Idiom

used to include sth in the list of things that you have just mentioned

British · Heard in 805 movies

not forgetting…
used to include sth in the list of things that you have just mentioned
I share the house with Jim, Ian and Sam, not forgetting Spike, the dog.

Definitions from the Oxford Advanced Learner's Dictionary, 9th edition

Well, you're not forgetting that this guy's not exactly stable?

Said in 8 films · #1