On Dexter, is her murder actually depicted?

Question

In the very end of The Getaway, I thought the bathroom scene to be another imaginary vision— one among many; it’s too contrived, too staged… his son sits in the pool of blood too much like he did, so I considered it to be a mere warning what might happen to his own family if he doesn’t change his ways.

I was puzzled accordingly when it turned out to be bloody truth. Then I thought I might have missed the scene where Arthur/Trinity overwhelms Rita and slashes her in the bathtub. But I didn’t find it.

Arthur breaks into Dexter’s appartment, only to find the D. to be Deborah. Then, right before the raid on the Miller’s home (Dexter hiding in the coffin), Dexter kisses Rita goodbye when she was headed for the airport. Then we see Arthur driving his convertible, right until Dexter finally gets and kills him.

Even if Arthur knew where the Morgans lived, how did he intercepted Rita’s cab to the airport? At what point in the timeline might this have happened? Is it merely implied? Is it a deleted scene?

Answer 1

Excerpt from Wikipedia's synopsis, which you actually linked to yourself:

Right before he is killed with a framing hammer, Arthur tells Dexter "It's already over." Disposing of Arthur's body on his boat afterwards, Dexter comes to realize that his love for his family is starting to outweigh his need to kill, and he begins to hope for a future without killing. But upon returning home, he finds a message from Rita that she came home from the airport because she forgot her identification. Dexter returns her phone call, only to find that Rita's cell phone and bags are in the house.

Presumably, Arthur was waiting in (or near) the house and ambushed her when she returned.