No one is expecting him to be awake at four in the morning. No one, in fact, is expecting him to be awake before around seven in the morning, it appears. The dorms' silence is only broken by the soft snores, and the common room doesn't have even that.
Professor McGonagall looks at the three of them, livid to the point that her lips are white.
"What on earth were you thinking of?" says Professor McGonagall, with cold fury in her voice. "You're lucky you weren't killed. Why aren't you in your dormitory?"
"I—I'm sorry, Professor, it's my fault," says Dayo. "I went looking for the troll—I just wanted to have a look—"
Now Snape turns to look at Dayo, with somehow even more disgust—and is that betrayal?—than usual. "I would not have expected this of a member of my House," he says, the careful emphasis betraying his opinion of certain other Houses.
"I noticed Dayo was missing and I couldn't find any teachers to tell about it," he says, looking up at Professor McGonagall. "I didn't know she'd gone after the troll on purpose; it seemed like the most important thing was to warn her quickly, so I went looking for her. I sent Muninn for you as soon as I found her. The troll was already nearby. And - I probably shouldn't have let Ron come along but it might have turned out a lot worse if I hadn't - he's the one who thought of dropping its club on its head."
"Well—in that case..." says Professor McGonagall, staring at the three of them, "Miss Iroko, you foolish girl, how could you think of going after a mountain troll on your own?"
"I'm very disappointed in you," she continues, either not noticing or caring about that. "If you're not hurt at all, you'd better get off to the Slytherin dungeons. Students are finishing the feast in their Houses."
Yeah she's not waiting for Snape to say anything about that. She quickly slips off.
She turns to Victor and Ron.
"Well, I still say you were lucky, but not many first years could have taken on a full-grown mountain troll. You each win Gryffindor five points. Professor Dumbledore will be informed of this. You may go."
Ron is completely silent until they've climbed two floors up, then grumbles, "We should have gotten more than ten points."
"I guess."
They reach the portrait and, after "Pig snout"ing it are greeted by a packed and noisy common room, with all the food. Ron makes a beeline for the pumpkin pie.