وَيَمْشُونَ بِهِ مُسْرِعِينَ دُونَ الْخَبَبِ
Translation: They proceed briskly with it, but not at a running pace.
Musri‘in means a suitably brisk pace, while khabab refers to a run or bouncing pace that can disturb the bier.
A hadith states: أَسْرِعُوا بِالْجَنَازَةِ
Translation: Hasten with the funeral.
The objective is prompt, dignified burial, not uncontrolled running.