What does 1 Samuel 29:4 mean?

But the Philistine commanders got angry with Achish and said, 'Send this man back to the place you gave him. He can’t go into battle with us, or he might turn against us during the fight. How better could he win back his master’s favor than with the heads of our own men?' 1 Samuel 29:4 - Modern Text Bible

(The other Philistine leaders don’t trust David, fearing he’ll betray them in battle to get back in Saul’s good graces.)