Lyra Belacqua, soon after she arrived at the Station, was measured by Dr Rendal who took photographs of her. During this, she asked him if he was measuring Dust and if he was going to cut the dæmons of the children at the Station away. He denied these and asked who had told her that. When Lyra told him the girls, he denied this, telling Lyra that the girls wouldn't have said that before asking where she came from. When the fire alarm went off, he cursed and shouted that it needed to be fixed before leaving the room just before Sister Clara, who had been supervising the experiments.
During a conversation with Dr Cooper later, the two discussed Marisa Coulter's imminent arrival and began drinking. Dr Cooper said to tell her that they were on the brink of discovery and to focus on the positives. Dr Rendal asked if they were really about to discover something as he was concerned. He asked her how many children would have to die before they got intercision right.
After Marisa arrived, Dr Rendal and Cooper assisted her and told her that more of the children were surviving the intercision process. Marisa then asked to see one of the experiments. At dinner that day, Lyra was asked to go with Dr Cooper. Halfway along the corridor to the intercision chamber, Lyra broke into a run however Dr Cooper ordered Rendal to pick up Pantalaimon and Rendal did so, horrified at breaking the taboo. When Cooper thanked him, Rendal asked if they were only doing what was necessary.
In the chamber, Rendal threw Pan into the cage and shut the door whilst Lyra was bundled into the opposite one. As Lyra struggled, Rendal told her to calm down and that the process wouldn't hurt and helped bundle the child into the cage. As a last attempt to stop the intercision from taking place, Lyra screamed that Mrs Coulter wouldn't want it. At this, Rendal stalled as Lyra knew the name of the woman.
As the knife rose into the air, Cooper urged Rendal to shut the cage so they wouldn't fritz the anbaro-magnetic system. As Rendal began to close the door, Lyra shouted that she was Marisa's daughter. As Rendal stopped closing the door, Cooper urged him on, telling him he was doing something great but Rendal asked if they should let her go as she knew Marisa's name. When Marisa entered shortly after and recognised her daughter, Rendal immediately gave the order to free them.
When Lyra later went to destroy the machine, she remembered the conversation about fritzing it and operated the machine with one of the doors open. Later, when the children went to escape the compound, Rendal rushed after them with two Tartar guards and ordered them to stop. However, some gyptians ran after the children, killing the two guards and Ma Costa went over to Rendal, grabbing him around the neck. She asked if he remembered Billy Costa, her deceased son, and he said it wasn't his fault and that he was only obeying orders. At this, Ma twisted, and broke, his neck, causing him to fall to the floor and killing him.