Tabitha felt herself being pulled. She recognized it was Donald, but she couldn't react because his action was unexpected, and her mind was still preoccupied with Silas's behavior towards her.
Donald pulled Tabitha to take her out of Silas's arms and assert his claim on her, to tell Silas that she was his.
For some reason, Donald couldn't understand why he hated how Silas touched Tabitha; he couldn't stand it, and he didn't know why. The image of Tabitha in another man's arms just didn't sit well with him.
Due to not wanting to handle his mate roughly and physically, which could hurt her, Silas loosened his hold on Tabitha. This allowed Donald to pull her out of his embrace, but Silas didn't let go completely.
Silas held Tabitha by her other hand and faced Donald, who approached to stand in front of him. They stared hard at each other in the eyes.