How far would you go to protect someone you love? Would you kill large groups of innocent people for medical testing?

That's what Frederick Barnes did on The Blacklist Season 1 Episode 7. In order to find a cure for his son's rare disease, he spread a modified fast-acting version of the disease in a train car that killed everyone on board. 

Of course, neither the FBI or Red knew exactly why Barnes went from being a highly respected scientist, to a scientist for hire to the highest bidder, and then finally to someone who distributed his work. Based on this shift, Red called him the "most dangerous man in the world." Based on his intellect, he could cause massive fatalities.

Liz and Ressler believed they uncovered the Barnes' motive when they found out that Barnes' secret son has Kurz disease. They thought he wanted to infect more people, draw attention to the disease and force interest in finding a cure. They were wrong. Barnes' plan was much more conniving than that.

After killing the train car full of people, Barnes' next target was a court room. And, his true plan was revealed. He was looking for someone with a with a natural immunity to the disease in order to use their bone marrow to save his son. 

The investigation felt off compared to the first six in The Blacklist season 1. For the first time, the show played more like other procedurals on television than a complex drama driven by the mysterious characters. And, for one episode that worked to highlight the importance of the partnership between Liz and Red.

Liz was still pissed off at Red for presumably setting up Tom. She didn't want to have anything to do with him, but for the good of the case communicated and met with him as necessary for the case. When he asked her to go to Cuba with him, she refused. And, he appeased her ... then.

Red was not about to let Liz go though. With the case solved, he pressed the issue. She wanted him to stay out of her personal life, but that was a non-starter. It was all or nothing. And, Liz's desire to protect people and solve cases superseded her disdain for him and his interference in her life.

While Liz believes that Red is trying to turn her against her husband, she's still intrigued by Red and the secrets that he holds. She doesn't seem to have any clue what he is holding out from her, but she has some sense that it's important or she wouldn't continue to tolerate him. 

It's not just about solving cases and providing her with extra status at the FBI, though that certainly has to play a part. Red does provide her some job protection. For example, Red may be her way out of disciplinary action after breaking protocol by giving up her gun and letting Barnes go.

This is personal and there is no avoiding it. And Red makes that crystal clear.

You know the problem with drawing lines in the sand? With a breath of fresh air, they disappear.

• Permalink: You know the problem with drawing lines in the sand? With a breath of air, they disappear....

From the previews, it looks like we may get some insight into what that all means in next week's episode, "General Ludd." While the connection between Red and Liz wasn't advanced in this hour, we did find out more about Red himself.

He had his associate, Luli, pay double in cash for a house. He wanted that house no matter the cost, but not to live in. His memories of the place initially appeared to be happy ones. He uncovered the height markings of a child on the wall and then remembered a girl playing in the yard.

Those memories made him smile momentarily, but then he left and had the house blown up. What happened to his family? We know he had a wife and daughter that he supposedly left behind when he went underground. Did something happen to them? And, was it before or after he turned to the criminal life? One thing that's sure is that Red's full of mystery.

Should Liz have agreed to Red's terms? Or, pushed him away? Does she really trust Tom 100% now? Or, does she still have doubts?

Carla Day is a staff writer for TV Fanatic. Follow her on Twitter and on Google+.