Zhou Can's Wound Cleaning Skill is currently Level 2, the lowest level of standardized training, not very advanced.
Handling this wound is more than sufficient for him.
If it weren't for Dr. Lu, that blockhead, using an electrosurgical knife to char both of the patient's bleeding points. The difficulty of cleaning the wound would have been even smaller.
As for when the fragments were removed, there was minor arterial spraying.
It's possible that when Dr. Lu was removing the fragments, the sharp edges of the fragments cut the blood vessel.
It's also possible that the fragment had initially punctured the blood vessel.
Before removal, because it was embedded in the muscle, it was tightly compressed.
So there was no bleeding.
After removal, the blockage at the rupture in the blood vessel was gone, causing blood to spurt directly.
This is why when someone is stabbed by a sharp object, and the object is stuck in the body, it must not be pulled out.