Is an explanation ever offered for why Nebula didn't just use her time travel watch?

Question

I'm confused. In Avengers: Endgame, for plot reasons at 1 second to go Nebula is stopped from hitting the time travel button to return to current time and Thanos gets to see her memories. The part where her and Rodey are going to go back together and he goes and she doesn't. Sure, I'll hit the "I believe" button on that healthy coincidence - build some suspense and such. I'll also hit the "I believe" button that her brain's neural network magically teleports its consciousness to the other Nebula, and that interaction leads to perfect playback of exactly the memories Thanos needs to see, and that this interaction not only causes this synchronization, but also causes an impromptu playback through her convenient plot-driving eye projector (we're really stretching but again, I'll hit that suspension of disbelief button [but boy we're pushing it])

What confuses me though is that then instead of just going back to the present day to tell people there's a problem, she runs back to her ship, tries to use a radio... or something [magic plot time communication device]?, then she sees Thanos approach, takes the ride up the ship-elevator-beam deal, gets hauled around unbound (as seen when she is thrown to the ground), and all this time she has the watch on, she still has Pym Particles... sooooo why didn't she you know... just return to her own time as planned in the copious amount of time she had to use the time travel watch? Is the answer pretty much "because plot" or is this reasonably explained?

Answer 1

Given the stakes, why would she even think about escaping, rather than using every last possible second and opportunity to try to radio a warning to her friends? Based on the script she appears have had ample time to get away, but her sole and overriding thought is to make contact with Barton and Romanoff, presumably even as she's in Thanos' beam and on her way to his ship.

INT. MORAG, TEMPLE VAULT - DAY (GUARDIANS)

ZZZT. ON THE FLOOR, NEBULA’S EYES SNAP OPEN, HORRIFIED.

NEBULA: He knows...

EXT. MORAG - DAY (GUARDIANS)
BOOTS POUND ACROSS THE ROCKS. NEBULA RUNS FLAT OUT, DESPERATE, HEADING FOR THE ESCAPE POD.

INT. ESCAPE POD - DAY (GUARDIANS) NEBULA rushes to the console and opens A COMMUNICATION LINK.

NEBULA: (INTO COM) Barton, Romanoff, come in. We have a problem. Thanos knows! Thanos

Suddenly, A SHADOW falls over the Pod. Nebula looks out the cockpit window...
AS A TRACTOR BEAM PULLS THE ENTIRE POD SKYWARD.

Even after she's on board, she still doesn't use the Time GPS, perhaps hoping that she'll somehow be able to escape and sabotage his vessel/get back to her ship/get to a comm. Once she pushes the button, that's it. She's off the board and it's game over for her.

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Note that she correctly recognises the clear and present danger that Thanos presents, as can be seen from this deleted scene where he, having failed to collect the Power Stone uses the data he's collected from her 'cloud memory' to make a play for the Soul Stone on Vormir.

Answer 2

Let's break down the relevant sequence of events here, using both Avengers: Endgame itself and the script for reference.

Firstly, in 2014, we see Rhodey with Nebula in the Temple Vault on Morag, having just obtained the Power Stone. With their mission seemingly complete, Rhodey jumps back to 2023 with the Power Stone, and Good Nebula is about to follow, when her memories are suddenly hacked into by Ebony Maw, from Thanos' ship, causing her to collapse to the floor, seemingly helpless.

She remains that way until Maw breaks the connection, and it's at this point that she realises that Thanos knows what the 2023 Avengers are up to.

INT. MORAG, TEMPLE VAULT - DAY (GUARDIANS)

ZZZT. ON THE FLOOR, NEBULA’S EYES SNAP OPEN, HORRIFIED.

NEBULA: He knows...

She then hotfoots it to the escape pod, where she tries to make radio contact with Hawkeye and Black Widow, who are also in 2014, attempting to acquire the Soul Stone on Vormir. She's unable to make contact though, before Thanos' ship arrives overhead and pulls the escape pod up with a tractor beam, with her still inside.

EXT. MORAG - DAY (GUARDIANS)

BOOTS POUND ACROSS THE ROCKS. NEBULA RUNS FLAT OUT, DESPERATE, HEADING FOR THE ESCAPE POD.

INT. ESCAPE POD - DAY (GUARDIANS)

NEBULA rushes to the console and opens A COMMUNICATION LINK.

NEBULA (INTO COM): Barton, Romanoff, come in. We have a problem. Thanos knows! Thanos-

Suddenly, A SHADOW falls over the Pod. Nebula looks out the cockpit window...

AS A TRACTOR BEAM PULLS THE ENTIRE POD SKYWARD.

The movie then cuts away to a couple of back-to-back scenes with Cap and Tony, the first in NYC in 2012, during the events of the first Avengers movie, and the second at a US Army base in New Jersey in 1970, where the Tesseract was stored.

The movie then cuts back to Thanos' ship in 2014, where we see Good Nebula getting roughed up by Bad Nebula, who promptly rips Good Nebula's time-space GPS from her hand.

INT. SANCTUARY-2, PRISON CELL - DAY

WHACK! NEBULA GOES TUMBLING ACROSS THE FLOOR. She gets to her knees, looking up at...BAD NEBULA, GLARING DOWN AT HER.

BAD NEBULA: You’re weak.

NEBULA : I’m you-

BAD NEBULA: Shut up!

BAD NEBULA PUNCHES GOOD NEBULA DOWN. GOOD NEBULA GROANS AS BAD NEBULA RIPS OFF HER TIME-SPACE GPS.

So from that point forward, Good Nebula simply didn't have the option to jump back to 2023. She did have a window of opportunity to use it before that, from the point that she woke up on the floor in the Temple Vault, at least up until the point that she was beamed up to Thanos' ship.

But what would she have achieved by going straight back to 2023, without letting the Avengers already in 2014 know that Thanos was on to them first...? The Avengers in 2023 didn't have any Pym Particles left, so it's not like they could send anyone else back to help. They were only in a position to affect events taking place from 2023 onwards.

The only Avengers that could prevent Thanos from getting hold of the Infinity Stones still in 2014 were the one already in 2014 themselves, i.e. Hawkeye and Widow, the very people that Good Nebula tried her best to contact.

In terms of whether Good Nebula had the opportunity to use the time-space GPS after being beamed up to Thanos' ship, that's unclear at best, since the first time we see her on the ship is when she's getting roughed up by Bad Nebula.