Most serial killers, if not all, never usually alter the course to kill you once you are in their grasp.
Not all use deception though.
However, if you research those that are very well known, on the most part those ones did and over and over again because they knew it worked.
Bundy with the pretense of broken arms and Dahmer with the lure of money for photos etc.
The Teddy Bear (think that is right) killer looked like a harmless gentle giant offering rides. His last victim was only let go because she was the spitting image of his very first victim.
The Pennsylvania serial killer going back decades (partially featured in Silence of the lambs I believe) deliberately targeted girls with disabilities or if they went missing - no waves. Eg Hookers.
Only one survived in the hell pit hole he imprisoned them in for the purpose of producing whatever sick fantasy he had in his head. They were slaves, dehumanised, and possibly breeding stock I think.
Sometimes people cannot be read - and by the time their true nature comes out it is farrrrrr too late.
DND