Final answer:
When treating a seizing patient with clenched teeth, the correct action is to remove dangerous objects to prevent injury and avoid inserting a bite block or restraining the patient.
Step-by-step explanation:
If you are beginning to treat a patient who is actively having a seizure and their teeth are tightly clenched, you should move dangerous objects out of the patient's way to protect them from self-inflicted injury. It is not appropriate or safe to force a bite block between the patient's teeth, as this could cause injury to the patient or the person attempting to insert the bite block. Likewise, restraint should be avoided unless absolutely necessary, as it can cause injury and increase the patient's distress.