لان الوجه في هذا الخبر حال الخوف والضرورة، والذي يدل على ان التيمم إنما يجب في آخر الوقت.
The context of this narration relates to a state of fear or necessity. Moreover, it indicates that tayammum is only obligatory at the end of the prayer's prescribed time, which is clarified through other supporting evidences.