boy entrant the pilot has no control about what response the ATCO orders up once they say there is a problem.
Some will do nothing, some will put a local standby on, and others will go for local call out, and others will go for the full monty with outside local emergency response.
The fire station listen in to the tower as well and even if the ATCO doesn't want the full blues and two monty the Head fireman may want to use it as an excuse for getting everyone out for training.
On the work machine I have had to descend down to 10 000 because of a pressurisation problem. Once down there we were happy for another hour of cruise. We also got met by the full works including incident van.
Most ATCO's don't have much of a clue these days about the different systems on board and work on the principle of better safe than sorry if there is any hint of something wrong.
The only way you can guarantee that you won't be met by the fire service if returning with a problem is by not telling the tower that anything is wrong. And making up some excuse about needing to come back eg I have the keys for another aircraft in my pocket.