In hindsight, it's always possible to call a perfect trading strategy for TPIV or any security. I wish it was so easy in real time.
In these clinical stage bio-techs, a stop loss can leave you out at a sharp, low volume, swing that leaves either out or having to get back in at a much higher price.
Or in a bigger decline, it saves you money and you can buy more shares cheaper or keep some profits. This time the better bet was the second one. Next time?
Some people are really in tune with the market swings. A combination of intuition and in sync chart reading. As all TA systems only work periodically, intuition is a big factor.