Well the fact that you're trying to solo it at low level is the problem. It's a raid event, you can request help from other players. You don't need to solo it.
Soloing is honestly only good for racking up PP. The faster you can kill, and assuming you get MVP each time, the more tickets and souls you can get in a day.
Though not sure how you can get the Ragnarok (Lv70) to 1/10th hp and not solo the expert one (Lv50). Unless you're completely unaware that there are other people helping you.