After everyone left Sam, Marcus finally had a chance to kill him, but something in Sam snaps as his inner darkness bursts out of him catching everyone's attention

Sam: YOU DID THIS TO ME!!! YOU MADE MY FRIENDS TURN AGAINST ME!!! YOU MADE ME PUSH THEM AWAY!!! I'M ALL ALONE BECAUSE OF YOU!!! I'M GONNA KILL YOU AND EVERY SINGLE ONE OF YOU WHITE FANG B*ST*RDS!!!!!!

sam roars with uncontrollable rage as he slashes at Marcus at full force

(This is not canon to RWBY vol. 8, this is a what if chapter)