[MRBAA]

You really have to think about situations like this in terms of expectation, not what happened in a particular hand or a few hands. Indeed, your reason for checking on fourth street uses this type of thinking -- sometimes an opponent will have a four flush, sometimes one will have an overpair. The same type of thinking on third suggests that you often have the best hand in this spot (no one has a higher door), so you bet to (a) thin the field (b) get money in while you are ahead. As the streets unfold, you get into negative implied odds territory, as your hand does not improve and other hands do. It happens that this time none of your opponents hit their hand, and you caught a good card on sixth. But I think you have -EV long-term on this play from fifth street on against the likely hands for your opponents with unimproved jacks. The pot was big here, though, so you were probably making less of a mistake and may even have been correct to draw at what may have been a 3 or 4 outer.

Without boring everyone, I'll just mention that the problem is that your outs may not be clean if your opponent happens to have a strong hand, or make one. And you will have to put in a bet on sixth if you miss, since the pot is now huge. And maybe even one on the river if you make something like a second small pair.

You've asked in other threads why your results aren't as good as you'd like. Here's a situation whre I think you initially got overly tricky and then took the worst of it hoping to suck out -- long term, this kind of play won't get the money imho.