If rack and opinion is not install correctly, cause the ignition key to have turn coming out?

Replacing a rack and pinion steering gear is a messy job because a lot of power steering fluid escapes. Most mechanics try to clean the area after the repairs are done but some fluid often runs into the cross member or frame rails where it can't be seen or easily washed out. You may smell that for a while until it all drips out or disperses. Other than the smell and possibly some spots on the ground, that won't hurt anything.

The key getting stuck shouldn't be related but logic dictates it is if this first occurred right after the last service. Have your mechanic recheck his work. There could be a linkage that got bent or mispositioned that he didn't notice, or it could just be a linkage needs to be readjusted.