Complex sentence: In the meantime, Tristan's plan to manipulate Sandrino's emotions worked and triggered his heart to beat again, but Malia's arrival tipped him off and he escaped before she could kill him.
Split into simpler sentences: In the meantime, Tristan's plan to manipulate Sandrino's emotions worked. His heart began to beat again, but Malia's arrival tipped him off and Sandrino escaped before she could kill him.