[Please do not make loud noises in the dormitory after lights out.]

I carefully put down the washbasin in my hands.

[Remember to close the doors and windows before going to bed.]

[There will be no one or anything outside the window watching you. If there is, please remain quiet and do not disturb it.]

Is it talking about the birds flying around on the eighth floor?

[If you hear a cry for help after the lights are out, please do not attempt to help the unfortunate violator. They may be undergoing punishment.]

I completely don't understand this sentence.

The horn's signal was interrupted by something, and the mechanical sound abruptly stopped.

Only the lingering sound of "zi... zi... zi..." remained.