It can be seen that the QCT calculated lines can be apparently separated into two stages, as evidenced by the significant change of the slope. The corresponding rate coefficients for the first stage are 0. for each 𝐸vib. This unusual case complicates the classification of CH3NC within the RRKM framework, suggesting that the molecule's dynamical behavior may not be fully captured by traditional RRKM theory. Theories, such as phase space theory, may provide insights for it.