Francois-Vivier Gagnon appeared before Quebec court Judge Jean-Pierre Boyer at a bail hearing Wednesday, as his lawyers argued he should be released after a dozen days in jail.
A grinning Gagnon acknowledged friends and family in the courtroom but appeared tense at times during the day-long hearing.
He'll have to spend at least one more night behind bars before Boyer renders a decision.
Three young women arrested with him were granted bail last week. The four are accused of tossing smoke bombs into various subway stations on May 10, shutting down service during rush hour and prompting a mass evacuation of the transit system.
The incident caused considerable panic in some stations and frustration for thousands of transit users.
Among the co-accused, recently bailed Genevieve Vaillancourt, 25, Vanessa L'Ecuyer, 22, and Roxanne Belisle, 23, each have to abide by 19 conditions that include a curfew and being forbidden from being near or in a metro or educational establishment.
The details of the Gagnon's hearing cannot be reported because of a publication ban.
The tense scenes at the courthouse during Gagnon's first appearance, including insults by supporters aimed at reporters, weren't repeated Wednesday.
However supporters and family used articles of clothing and bed sheets to block news cameras from taking their images.
Gagnon, 22, faces charges of perpetrating a terrorist hoax; mischief of more than $5,000; conspiracy to commit mischief and possession of a prohibited weapon. According to the charges, the weapon was a butterfly knife.
The charge of perpetrating a terrorist hoax carries a maximum five-year prison term. Gagnon has been detained since May 11 after turning himself in to police.
Defence lawyer Veronique Robert says she's confident her legal team has made its case that Gagnon should be released.
She said outside the courtroom that the Crown could have consented to Gagnon's release with the other three co-accused last week.
But the prosecutor wanted Gagnon to remain detained because he faces a pending case over a student strike-related incident at a Montreal college a few months before the metro events.
"The accused has a pending file," said Crown prosecutor Steeve Lariviere. "It's his burden at this point to convince the court that he doesn't represent a danger to society if he's released on bail."
Boyer will render a decision Thursday morning.