Luke was quite surprised by the system notification.
As a classic bad guy with "suspected knock-off Iron Man armor" and who spouted a lot of supervillain lines, Ivan was only worth 200 points.
He was simply a disgrace to villains.
Also, according to the experience and credit points from this mission, he probably hadn't come here to hurt anyone except Tony Stark.
Also, while he was tagged as evil in the system, it was the lightest shade of red.
Light red meant minor evil, and the level of danger was on par with a standard hooligan; anyone who stole things or sold weed more often would be included.
Coupled with the 200 points assigned by the system, this meant that this Ivan actually wasn't too bad. He had just done some bad things at most, which was really unexpected.
So, instead of killing him, Luke decided to hand him over to Tony.
Of course, experience and credit were just one of the gains.