Allergic Reaction - Cardiology?

I'd presume General Internal?

I’ve also found that Cardiac Arrests go to traumatology as opposed to Cardiology

Allergic Reactions can have cardiac related issues, so it can entirely possible. Allergic Reactions can change into a cardiac arrest if the airway closes

Cardiac Arrest going to a traumatology due to it being trauma causing the arrest not the heart itself

Respiratory Arrest is where respiration stop, but not the heart

Airway closing would be respiratory arrest, and like all respiratory arrests, if it not dealt with promptly, will further develop to a cardiac arrest due to lack of oxygenation.

As for other points, both allergic reactions and cardiac arrests should go to general internal, as any ER has the capability of dealing with both and time requires the nearest open ER be the patient destination. Also, if the cardiac arrest is due to trauma, it is called a traumatic arrest. General internal would still be appropriate for this patient, however, some jurisdictions may have a bypass policy in place depending on the proximity to a trauma centre.

I have brought this up before, but the mods have stated that they are assigned those specialties to fill the need for the specialty, and as medical recently got a lot of attention, it was not likely anything would change anytime soon. Not sure if that is still the case though.