I chose the second option, as if direction intervention would lead to significant risk to myself then I would seek the help of the authorities. However, if there was not a significant risk to myself, such as if the person had a medical episode for example, then I would directly intervene until help arrived.
Regretfully, I have had one incident like this which occurred about six months ago. I was walking from one building on campus to another when I heard someone yelling for help in a nearby parking lot. I ran to the scene to see a woman collapsed face down on the pavement with one person trying to get her to wake up and several onlookers doing nothing. Remembering what I learned during my emergency training courses, I specifically called on one of the onlookers to get help (i.e. "You. Call for an ambulance now!") and I ran to get immediate help (as I am not a medical professional). Luckily for this woman, she had collapsed in the parking lot right next to the nursing offices on campus, so there was no shortage of nurses, nurses aides, and doctors in the vicinity. I knocked on a few doors and interrupted a nursing class in order to get some help. Thankfully, they were able to get the woman stabilized before the EMTs arrived.
The bystander effect is something that makes me incredibly angry. It never ceases to amaze me how just asking on one person to do something suddenly changes their psychological perspective from "it isn't my problem" to "it is my responsibility". In the case that I mentioned, thankfully the woman only suffered from mild complications. Considering the 20-something year old woman had had a stroke with loss of consciousness, obvious cognitive impairment, and severe seizing, it could have been far worse.