There are a few things to be said here. First, it should not crash and a future version will behave better in this scenario. What I am not quite sure abuot is why the call
ToElementMesh[DiscretizeRegion[...]] in the first place. Note that both
mesh = ToElementMesh[\[CapitalOmega]];
work fine. In your example you first make a mesh region and then remesh to make an
DiscretizeRegion will return a first odrer mesh
ToEM[DR[...]] will (should) return a first order mesh. You can get that diretly with
ToElementMesh[region, "MeshOrder"->1]. Additionally, the quality of the mesh will not be as good as it could be since
ToEM has no way of knowing what the exact boundary is in
Now for the real problem: When you do a direct conversion from the mesh region to an element mesh via you get a message:
mr = DiscretizeRegion[\[CapitalOmega]];
ElementMesh::femimq: "The element mesh has insufficient quality of -0.0124712. A quality estimate below 0. may be caused by a wrong ordering of element incidents or self-intersecting elements."
So the mesh region has bad elements. This is fixed in the development version. It might be good to have this message also in the
ToElementMesh[DiscretizeRegion[...]] case such that one knows that the returned element mesh is wonky.
Another note, ploting a "Wireframe" should work in many cases - even if the mesh quality is less then zero. The reason for that is that then one can still look at the mesh and possibly find the bad elements. While this may not be possible in this case, it's useful for smaller meshes.