swim for it
1. To attempt to reach something or some place by swimming, especially as a last resort. Our boat had almost completely filled with water before we were able to reach the shore, so we had to swim for it the rest of the way.
2. To attempt to escape (someone or something) by swimming. The prison is on an island, so anyone who tries to escape will have to swim for it in shark-infested waters.
swim for it
to escape by swimming. (See also run for it.) I escaped from the guard, dived into the river, and swam for it. Max swam for it, but he didn't get away.