So as to not expose the truth. I’m unsure about the background of the question
The participle is "digging." Most participles end in -ing. It modifies "man", describing what the man is doing.
Answer:
Use Sentence Fragments Sparingly and When the Story Calls for It. Sentence fragments in fiction can be a useful way of conveying pace, tone, and intensity. However, overuse can lead to lazy writing—fragments should be used sparingly, and for a good storytelling purpose. I think it’s when the cast of characters includes just two characters I’m not 100% right on this