Do not forget that there is a standard procedure (which we all pilots know) to be followed in the event of a two way radio failure.
There is also a procedure to be followed when/if an unknown traffic is detected in order to let the interceptors identify the intruder and then, by visual signals, let him continue, or to force him to follow another track or to land on the indicated airport.
I cant believe that everything has not been executed to the letter.