“The Blacklist” has had the tradition of eliminating its villains during the 10th episode mark over the past three seasons, so it was already expected that Season 4 shall have Kirk as the victim. It would have t been good if Kirk met his end at the hands of Liz, who also have an ax to grind against him not only for pretending that he is her father but also for kidnapping her daughter Agnes and holding her as sort of hostage.
Also during the eighth episode, Red was able to force Dr. Shaw to give the location of a former patient, the whereabouts of whom led to the location of Alexander Kirk.
After Red unmasked who Alexander Kirk really was, the speculations have gone back to him as the real father of Liz as it has been rumored previously that he and Katarina Rostova, Liz’s mother, had an affair in the past.
That is why Red has always had a soft spot for Liz and he always makes sure she is safe in everything she does, which suggests that she could be more than just a friend or a partner with the FBI for her.
Episode 8 also saw Liz running after Alexander Kirk and doing everything in her power to make sure that he does not escape from the hospital. Apparently, Kirk did but it was Red who caught up to him.