From the moment the Joker had accepted the job Olivia had given him, he had been watching Laila's every move as well as any news or whispers surrounding Noah and I.E.. He got part of his whispers from companies making a delivery, disguising himself as just another delivery man himself to get them to make small talk with them and get the information he wanted. That is how he knew about the event and it didn't take long for him to find out when and where it would be taking place. Once he had that information, he still had plenty of time to figure out how to make use of said event.
Of course this wasn't the only situation he was considering, but he felt it would add a nice touch, since he could harm both Laila, Noah and the company with one proverbial stone. But when it became clear that Laila would be going separately from Noah, he knew this was the perfect opportunity for him to carry out his task and let go of the others he had in mind. He knew that being apart from Noah would put her in a more vulnerable state. Her getting hurt in the one situation where he was absent, would add a great deal of guilt to Noah's emotions after the fact and inflict an even greater deal of hurt than if he had been present as well. Although that wouldn't have deterred him from attacking their car on their way to the event, Noah not being there added a certain sense of 'charm' to it all in the Joker's twisted mind.
He told all of this to the detectives with a wide grin on his face, much like the Joker from the Batman franchise. Not needing any type of pressure to confess his crimes as he was more concerned with getting credit for his actions than not being punished for them. While no sane person would be able to understand this reasoning, Max, Jack and the detective certainly had no complaints. Max and Jack were discussing the Joker's madness amongst themselves behind the one way mirror from which they were following the interrogation, if you can even call it that when the person confesses to everything and more without even being forced to do so. As they listened to him talk, they felt their own anger towards the situation rise. When they felt they could listen to the man no more, they stepped out and called Noah once more to tell him what had happened.
Noah felt anger that a man like this had been able to read his emotions so well and had taken advantage of his own carelessness. But his story had also made him realize that he was insane and the law wouldn't be able to punish a man like him the way he deserved, without a helping hand from him. Although Noah had no plans of dirtying his own hands, he had some connections that would help him end up in the right type of prison. Spreading word of him attacking a pregnant woman, would surely get some people's blood boiling and ensure the Joker coming to a messy end. While he only did what he was asked and paid to do, he should have known better than to attack his wife and a man as twisted as him, was better kept off the streets indefinitely.
With that in mind, Noah ended the call with Max and immediately made another. Jack and Max had successfully done what they had set out to do and now felt that they could return to the hospital in good conscience to wait with the others for Laila to wake up. In Jack's case, he still had some medical treatment to undergo, which he stopped prematurely in order to catch the Joker and clear his guilty conscience. Having heard from Max that Laila had pulled through the surgery, had eased most of his worries and once the people responsible had been punished, he could close this dark chapter for good.
When Max and Jack arrived back at the hospital, they were received by Maria, Noah and Steve with open arms for what they had managed to do in such a short amount of time. That is also where they received the good news that Damian had woken up and was doing well, while Laila seemed to need a bit more time to open her eyes. Being in a deep dream, where nothing seemed to reach her, despite the doctors saying that she was physically okay.
Although Laila not waking up yet caused Noah to feel a worry in the back of his mind, wondering if this meant that she might not wake up anymore at all, he pushed those thoughts away for the relief that she had not lost her life in the accident at least and that she hadn't lost another child. He had seen the hurt in her eyes when she told him about the loss of the baby she and Jake had in her previous life. He wasn't sure if she would be able to recover if she lost another one in this life, especially with their names being so similar and her seeing this as the baby from her previous life coming back to her. Now he needed to have faith in her desire to come back to him and actual live the life she fought for, with him and their baby boy.