I think that your colleague was mistaken to intervene with your student in your presence. That was wrong.

But I think you should consider whether or not it is a good idea to let students coming to class late “slide” — especially when they respond to an inquiry that way this student did. Before too long, you may find that every student feel entitled to come to class late when they feel like it. And if you challenge it then, the response will be “what about so and so?”

Here’s a third alternative. You ask a student why she is late, and in front of the class, she gives a snotty non-answer that she was hanging out in the hall — a direct challenge to the idea that she has a responisbility to be on class time. You simply say, “Please stay after class so we can discuss this.” And then, after class, with no audience, you and she have the discussion about being to class on time. The rest of the class gets the message that being late is not acceptable, and that being snotty to you when you ask a question is not acceptable.

Glad to hear things are looking up! I really meant what I said the day you were excessed: Where a new teacher’s career is concerned, what doesn’t kill you (and there’s very little chance of that) makes you stronger. Plus, you appear to have wound up in a better working environment.

Congratulations, and continued good luck!