Futures vs market activity

So overnight the spy/eminis traded in a 1120-1140 range. I figured that trading off either of those extremes would be good for a daytrade-fading whatever extreme was approached. I did this with very little pain this am. I took a look at what I think the math could be for this one trade if it was eminis. For one contract I could have pulled in $300, for my goal of 10 contracts it could have been 3K in gain in less than 30 minutes. Intraday margin requirement, if I am correct, would have been just over 14K to make that trade. In my opinion, it was low risk, decent reward scenario. I got a 1R gain out of this.