I'm not sure what you mean by "safe". Do you mean crossing irregularly / not at an official border crossing? Hopefully you are aware of the recent changes to the Safe Third Country Agreement. You must meet one of the exceptions under the agreement in order to have your refugee claim accepted (regardless of whether you enter as a regular or irregular crossing). Otherwise you will be returned to the US. Assuming you meet one of the exemption critiera and qualify to file a refugee claim in Canada, you might as well cross at an official / regular border crossing.
Due to the safe thirst country act (STCA) a family member would not be able to enter Canada unless for very specific conditions like being a minor travelling alone. If you only have a family member that is also applying for asylum in Canada you would not qualify for an exception from the STCA and would likely be deported back to the US. You aren’t limited to living in Detroit.