Board Thread:General Discussion/@comment-24204226-20140224050548/@comment-4872828-20140227141838

He might track her, but I don't think he's going to menace her the same way as in that episode.

In comparison to all the other mutants (even the ones who had seen to act solely on instinct) who made a beeline for that exit as soon as they were able to Donattello had to urge Kirby to go through. His pause was only for a brief second, and it was probably more Kirby being momentarily stunned than anything else, but it does indicate he's nowhere near as out of control as he was in that first episode.