Why was Molly still wearing her cloak?

Question

Voldemort was in the center of the battle, and he was striking and smiting all within reach. Harry could not get a clear shot, but fought his way nearer, still invisible, and the Great Hall became more and more crowded as everyone who could walk forced their way inside.

Harry saw Yaxley slammed to the floor by George and Lee Jordan, saw Dolohov fall with a scream at Flitwick's hands, saw Walden Macnair thrown across the room by Hagrid, hit the stone wall opposite, and slide unconscious to the ground. He saw Ron and Neville bringing down Fenrir Greyback. Aberforth Stunning Rookwood, Arthur and Percy flooring Thicknesse, and Lucius and Narcissa Malfoy running through the crowd, not even attempting to fight, screaming for their son.

Voldemort was now dueling McGonagall, Slughorn, Kingsley all at once, and there was a cold hatred in his face as they wove and ducked around him, unable to finish him - Bellatrix was still fighting too, fifty yards away from Voldemort, and like her master she dueled three at once: Hermione, Ginny and Luna, all battling their hardest, but Bellatrix was equal to them, and Harry's attention was diverted as a Killing Curse shot so close to Ginny that she missed death by an inch -

He changed course, running at Bellatrix rather than Voldemort, but before he had gone a few steps he was knocked sideways.

"NOT MY DAUGHTER, YOU BITCH!"

Mrs. Weasley threw off her cloak as she ran, freeing her arms, Bellatrix spun on the spot, roaring with laughter at the sight of the new challenger.

"OUT OF MY WAY!" shouted Mrs. Weasley to the three girls, and with a simple swipe of her wand she began to duel. Harry watched with terror and elation as Molly Weasley's wand slashed and twisted, and Bellatrix Lestrange's smile faltered and became a snarl. Jets of light flew from both wands, the floor around the witches' feet became hot and cracked; both woman were fighting to kill.

"No!" Mrs. Weasley cried as a few students ran forward, trying to come to her aid. "Get back! Get back! She is mine!"

Hundreds of people now lined the walls, watching the two fights, Voldemort and his three opponents, Bellatrix and Molly, and Harry stood, invisible, torn between both, wanting to attack and yet to protect, unable to be sure that he would not hit the innocent.

Harry Potter and the Deathly Hallows (The Flaw in the Plan)

What makes me wonder (and worry), is that Molly Weasley joined the second to last fight, and only then did she remove her cloak. She was in the midst of a battle, right in the center, very near to both Voldemort and Bellatrix, and she still had her cloak on. Why? Wouldn't the cloak slow her movements? She could have been healing people but the fact that she could have hit by a stray killing curse because she couldn't dive or that she could have hit by a stray Bombarda or Reducto because she couldn't bring her wand up to cast a Protego still worries me. And even then, no Death Eater would ignore the chance to kill someone just because he/she was healing people.

Was this an oversight on J.K. Rowling's part? If not, why did Molly still have her cloak on throughout a vast majority of the battle?

Answer 1

She had no reason to take off her cloak until then

Mrs. Weasley arrived in the Room of Requirement with everyone else, and let's assume she was wearing her cloak when she arrived:

As the room came into view, Harry slipped down a few stairs in shock. It was packed, far more crowded than when he had last been there. Kingsley and Lupin were looking up at him as were Oliver Wood, Katie Bell, Angelina Johnson, and Alicia Spinnet, Bill and Fleur, and Mr. and Mrs. Weasley.

A few minutes later she left the room:

Mr. and Mrs. Weasley and Lupin headed off for the stairs as well.

Next we see her in the Great Hall:

Harry hurried over to the Weasleys, all sitting together at the Gryffindor table.

Then the battle tasks are assigned:

"We’ve only got half an hour until midnight, so we need to act fast! A battle plan has been agreed between the teachers of Hogwarts and the Order of the Phoenix. Professors Flitwick, Sprout and McGonagall are going to take groups of fighters up to the three highest towers – Ravenclaw, Astronomy and Gryffindor – where they’ll have a good overview, excellent positions from which to work spells. Meanwhile, Remus," he indicated Lupin, "Arthur," he pointed towards Mr. Weasley, sitting at the Gryffindor table, "and I will take groups into the grounds. We’ll need somebody to organize defense of the entrances of the passageways into the school –"

"– sounds like a job for us," called Fred, indicating himself and George, and Kingsley nodded his approval.

"All right, leaders up here and we’ll divide up the troops!"

Notice that Mrs. Weasley is not assigned a specific task in this passage. It is possible that she remained in the Great Hall away from the battle, and thus had no need to remove her cloak. It is also possible that she was one of the "troops" assigned to a group, all of which were to operate outdoors, so she may have kept her cloak on for that (especially if she was in a group on one of the towers where ease of movement would be less important as they wouldn't be directly in the thick of the battle).

We next see her in the intermission, where she is in the Great Hall lying across Fred's body:

The dead lay in a row in the middle of the Hall. Harry could not see Fred's body, because his family surrounded him. George was kneeling at his head; Mrs. Weasley was lying across Fred's chest, her body shaking, Mr. Weasley stroking her hair while tears cascaded down his cheeks.

If she had been away from the battle the whole time she would still have not had a need to take off her cloak. If she had been fighting outside she would still be wearing it and would likely not have stopped to take it off when she saw that Fred was dead.

When Voldemort returns to the castle with Harry's "dead" body, the defenders come outside:

He squinted again for a single second and saw the open doorway filling with people, as the survivors of the battle came out onto the front steps to face their vanquishers and see the truth of Harry's death for themselves.

There is nothing to indicate that Mrs. Weasley was among those who came outside. It seems more likely that she would have remained in the Great Hall crying over Fred. In fact, there is almost an indication that she did not go outside: Harry hears the terrible screams from McGonagall, Ron, Hermionse, and Ginny when they see him "dead", but nothing from Mrs. Weasley. Had she been there she would probably have let out a terrible scream as well.

The battle eventually restarted, and eventually made its way back into the Great hall. However, it doesn't seem to have gone on for a long time in the Great Hall. By the time Harry gets into the Hall, he already sees everyone besides Voldemort and Bellatrix get defeated before he can even do anything:

Harry saw Yaxley slammed to the floor by George and Lee Jordan, saw Dolohov fall with a scream at Flitwick’s hands, saw Walden Macnair thrown across the room by Hagrid, hit the stone wall opposite and slide unconscious to the ground. He saw Ron and Neville bringing down Fenrir Greyback, Aberforth Stunning Rookwood, Arthur and Percy flooring Thicknesse, and Lucius and Narcissa Malfoy running through the crowd, not even attempting to fight, screaming for their son.

So it is possible that there wasn't much time for Mrs. Weasley to join the fray, even if she had wanted to. I would argue that she wouldn't have joined anyway; she would have still been with Fred, too consumed by grief to do anything else, and not even caring about the various curses flying all around her.

However, at that point Bellatrix nearly kills Ginny:

Bellatrix was still fighting too, fifty yards away from Voldemort, and like her master she dueled three at once: Hermione, Ginny, and Luna, all battling their hardest, but Bellatrix was equal to them, and Harry’s attention was diverted as a Killing Curse shot so close to Ginny that she missed death by an inch ―

The threat of her daughter being killed awakens her maternal protective instinct, and that is finally enough to tear her away from her grief with Fred, and propel her into the battle. Now that she has finally joined the battle for real ("both women were fighting to kill"), and she is indoors, her cloak would be a hindrance. Therefore, at this point she finally takes off her cloak, because this is the first time that night that she really needs to take it off.