To reap third-party profits by taking advantage of a conflict between others.

profit reaped by a third party when two sides are locked in a dispute, or profit gained at the expense of others who are in conflict

To take advantage of a situation where two parties are in conflict to gain an advantage as a third party. This is a shortened form of the idiom [[鹬蚌相持，渔人得利|鷸蚌相持，漁人得利|yu4 bang4 xiang1 chi2 yu2 ren2 de2 li4]].

literally: when the snipe and the clam grapple, the fisherman profits; used to describe a situation where a third party benefits from the conflict between two others