Dumbledore was absent from the castle.
And he made it sound like the wards only alert him when a student has died. It's reasonable to expect them to warn ahead of time, after serious injury or something, but going by canon Dumbledore had no external alarm when Harry broke however many bones however many times on the Quidditch pitch.
When I'm not in the mood to talk to people- not out of anger, I'm just not feeling a desire to share my thoughts- I think in pictures and feelings with a reticent, sarcastic monologue. When I'm alone but feeling social, my monologue is wordy and sometimes witty. When I'm in a conversation, I often have to stop talking for a moment to think through what I'm going to say before I can say it.
Bottom line, I almost always have some kind of monologue; sometimes it's talkative, sometimes nearly silent.
Snake detecting spells: Canon!Harry sucked at Occlumency.