Yes, it is possible to make an exception and check-in visitors who fail health screening. Such guests will be redirected to the front-desk staff by the iPad app, and the front-desk staff can allow them entry.
The staff would need to input the reason for allowing entry before a badge can be printed for the guest.
The Visitor records will display that the guest had failed the health check and an exception was made.
It is also possible to review the health check answers for each individual guest if required.