What exit does inside of an END block is set the exit value ($?) and exits the remainder of that END block, any remaining END blocks are still called in reverse order of definition.

    print "Hello World\n";
    exit 0;
    print "Goodbye World\n";

    END{
        print "End 1\n";
    }
    END{
        print "End 2\n";
        exit 1;
        print "End of End 2\n";
     }
    END{
        print "End 3\n";
    }

# output:

    Hello World
    End 3
    End 2
    End 1

# exit status:
    256
[download]