Did he? Loki and Imu were staring each other down while Imu happily yapped away and Loki was increasingly confused, then Luffy showed up and punched Imu. Then Loki stopped focusing on Imu, started bickering with Luffy, then got hit by the flames that serve as a target for Stigma. That.....doesnt sound like Luffy saved him from anything. Its not like Loki was about to get hit by an attack and Luffy stopped it. That just sounds like a distraction that got Loki folded.
Now, not saying Imu couldn't have done that anyway without Luffy there (he almost certainly could if he really wanted to), but Luffy definitely didn't HELP in any way. Lol. Spinning that as him saving Loki is kinda diabolical on your part, big fella.