With others, I cannot even be sure what the "take away message" is supposed to be. "took length to" does not make sense. "length" is a form of measurement, applied to an argument, "length" implies a duration of time. Is the teacher measuring the length of the argument? That is not a plausible action for a teacher.
So no, I don't think the word 'length' is helping you at all, it is just confusing.
I will also agree with Morgan that 'chalk drenched' sounds wrong; 'drenched' is for something in which a liquid drenching is a an appropriate metaphor, and chalk is a particularly dry and dusty solid. Unrelated to your question, I would suggest you DO increase the length of the passage, perhaps to multiple sentences, to convey the message you want.
Namely, I think the message is: Your pleasant daydream was interrupted by a quarrel, forcing your attention back to the tedium of blackboards covered with notes and equations as dry as the chalk that wrote them, and waited for the teacher to resolve this annoyance.