Chiheb Esseghaier was determined to forge ahead with the alleged terror attack even after Raed Jaser backed out of the project, their trial heard.
Not-guilty pleas have been entered for both men, who face multiple terror-related charges in the alleged plot targeting a train travelling from New York to Toronto.
Through secret audio recordings of conversations they had with an undercover FBI officer, court has heard about how a brief encounter with police on a scouting mission in September 2012 led Jaser to abandon the alleged train plot, although he was still interested in coming up with another attack.
An angry Esseghaier, however, sought to move on from Jaser and was heard telling the undercover officer he was glad his co-accused was no longer working with them.
"He will impede the project, he will make us lose," Esseghaier is heard saying of Jaser. "He has some sickness in his heart."
Esseghaier added he would "disown" Jaser and make finding a new recruit a priority, court heard.
"The one who is scared, we don't need him...this work needs a bold heart," he is heard saying.
Esseghaier, a Tunisian national who was doing doctoral research in Quebec, first named an Afghani man living in Ontario as a potential replacement and later mused about a man from Saudi Arabia and one from Tunisia as well, court heard.
He also detailed a plan to reach out to a jihadist contact in Iran for information on an American "sleeper" who might be able to help, court heard.
"I have to meet the sleeper of the U.S.A.," he is heard saying. "Maybe the sleeper, he know a big group of persons."
The court has heard that Esseghaier travelled twice to Iran and established contact with "mujahedeen brothers" there. Esseghaier has been heard saying one of them was called Al Massoul, a member of Al-Qaida who told him to purse the train plot.
Al Massoul sat "thigh to thigh" with "Sheikh Osama," Esseghaier told the undercover officer, and gave Esseghaier instructions on how to carry out jihad in Canada, court heard.
"He told me the first thing to do...gather the cells around you to create the group," Esseghaier is heard saying. "The second priority is...awaiting orders related to the projects."
Despite their dealings in the past, however, court heard that Esseghaier was having a hard time getting directly in touch with Al Massoul, who in turn was to connect him with the American "sleeper."
Esseghaier is heard expressing his disappointment but vows to remain patient, the trial heard.
"He knows I am waiting for him," Esseghaier is heard saying. "We are in need of believers."
Jaser and Esseghaier were arrested in April 2013.