There is an inconsistency here with the way that NCrunch handles situations like this vs other test runners.
For reasons of simplicity, NCrunch doesn't have an 'inconclusive' state for tests that have been executed. This means that should a test report an inconclusive result at runtime (such as the one you've described above), NCrunch will still consider the test as having a pass/fail result as it has no way to represent the different response from the test.
There is a project-level configuration option you can use to control how NCrunch should respond to an inconclusive result, it's called 'Consider inconclusive tests as passing'. This may or may not be of some use to you.