You are too stupid, he wasn't fighting anyone there.
Lakainu was already fighting but he chose a momentary retreat vs Marco due to Marco's power was a threat to him.
Teach had no intention of fighting with Marines in the first place there, was just waiting for a transition not waiting for a fight, similar to WB retreating vs Fodder Marines, and Mihawk vs Fodder Marines, they weren't planning to fight anyone so they retreat.
Mihawk attacking Daz Bones and others, but then stopping when it comes to Jozu, Vista and Croc proves, they are capable of damaging Mihawk, because Mihawk had intention of fighting in Marineford but they are strong enough to damage him so he momentarily stops similar to Lakainu vs Marco.
You think Koby was crying for dying WB Pirates?