Having
"Electronic Counter Measure (ECM) resistant [communications] with secure and non-secure UHF and VHF dual redundancy"* (which I translate as "2 radios") will let the single pilot operate on multiple frequencies and talk to the intercepted aircraft whilst remaining in communication with the military agencies.
I would expect that procedural limitations of the task/situation may mean that making direct communications with the problem aircraft aren't a high priority.
*source: Eurofighter Typhoon - Navigation