Welcome to NeuroTalk:

I can under your concern and confusion.

Your blood pressure is not high, even under those stressful
conditions at the hospital!

I agree with en bloc's advice.

There are many issues that can lead to a TIA.
If you are young and female, hormones will do it. Birth control or hormone replacement therapy.
Also autoimmune diseases change the coagulation of the blood,
and may lead to a clot. Lupus is one, but others less common exist like en bloc describes. All of these triggers, are for clots.
They make up the majority of strokes. Excessive platelet counts could also thicken the blood. Some cardiac rhythm problems can induce a stroke.. atrial fibrillation is one cause. This is where the atrium part of the heart stops beating and the blood sits there for a time, and then clots, so when the beat returns it can send a clot off to the body. This typically has dizziness or fainting as a symptom.

But there are hemorrhagic strokes too, where a blood vessel bursts. These may be triggered by increases of blood pressure.
Aneursyms are present from birth and may rupture anytime,
and not always need a high blood pressure to do so.
Our blood pressures change with activity levels, and may go as high as 200 when exerting ourselves. The body normally adjusts to this, and it is only for short periods of time.

You'll need to see your regular doctor, for some further testing and evaluation.