That's what it sounds like; and perhaps the detonator was only triggered by accident. That is, maybe he was in the men's room because even a terrorist probably feels the call of nature, wishing to be fully comfortable as he goes off to meet his virgins (or maybe he was doing something odd like shaving off all his body hair in the men's room).
In any case, I would doubt that the Tim Horton's (sort of like a Krispy Kreme in the US, I imagine) was the real target of this.