Using Multiple Time Frames to Exit a Trade

SPY has been giving me fits lately, so I've been looking at other alternatives. A "narrow candle" trade setup on SYNA this morning so I took it. I risked 15 cents per share and gained about a buck per share for a 6.66R trade. It's been a while since I've had that much of an "R" gain on a trade. It's much harder to find those kind of risk to reward ratios trading indexes.
I've always struggled finding decent exits with these narrow candle trades. Using the 15 minute chart in conjunction with the 30 minute provided a great exit--the doji at 2:30 (red arrow). Unfortunately, I was away from my computer when it happened, so I exited at a less-than-perfect spot.