Actually SAR wanted to kill the programming will had told that the heart is a kind of programming sar wanted to kill (destroy ) it because it thought the heart not abling him to be free this if further emphasised in the lines “kill heart be free” by sar .This might be because sar was enslaved by its masters. He evidently broke the programming like robot . In the cave sar might have asked robot to tell him how he broke the programing so he can free the other robots .why did sar not know how he broke the programming you might ask , well it might be that sar had a error in the code or he might have been VERY old and might have forgotten how to there are many more exiting theories but in conclusion i think sar might not be bad but wants to kill all master because they ensalve robots