Muninn meets them at the base of the tower and swoops down onto Victor's shoulder. "Message delivered."

"Thank you, Muninn."

And they go up the stairs and Victor gives the password.

And they're in and Neville flops down on the ground.

"Are you all right?"

He does a thing with his head that's probably a nod and a head shake at the same time.

"Come on, let's go upstairs and go to bed."

He takes a few seconds but eventually manages to get up and follow Victor.

Victor seems strangely unperturbed by this experience.

He goes to bed and lies there and covers his head with his blanket and closes his eyes and hopes it was all a dream.

Victor curls up in bed and tries to figure out how he could have done that better. Maybe if he'd sent Muninn around the corner instead of leaving the portrait himself...

"Pss," Ron calls from his bed.

"Yes?"

"Where were you?" he whispers.

"Neville was locked out of the tower because the Fat Lady left her portrait, and then we saw Mr. Filch's cat and had to run away and got lost for a little while."

"Oh. How'd you find your way back?"

"We eventually came to a place I knew how to find my way from." Pause. "It was the forbidden corridor on the third floor. There's a giant three-headed dog in it."

"What?" Ron exclaims.

"Be quiet, Weasley, we're trying to sleep," Seamus grumbles.

"I'll tell you about it tomorrow."

"...okay."

Sleep.

Then: morning!

And does Ron ask him about the corridor?

As soon as they're reasonably isolated, yes!

"There was a giant three-headed dog."

"Why was there a giant three-headed dog, what was it doing there, how are you alive?"