While some of the healers were unsure of where the skills and confidence came when speaking to Clark, they didn't hesitate to let him act as he needed to. They watched for a moment and put themselves in position to keep their work moving. They were professionals and they did not need to worry about other things. They had to focus on the tongue ess that was helping an arm regrow.
Since they had already helped Leo drink condensed nutritional potions and made a salve that helped the body control the energies within it, it was time for them to use their beasts and their skills to regrow an arm. This was a very intricate process that required a higher level of healing. That was why someone experienced like Pia was needed.