Not A Goodbye.
The Queen Industries building in midtown Gotham explodes as he looks on, and Robert Queen calls this a job well done. He planned the attack for after-hours, when the least amount of people were there. He'd counted two guards and someone working late in an office, all of which were disabled and removed from the building before its destruction.

Innocents didn't deserve to die for Oliver Queen's sins, though the resulting joblessness would be an issue until the place was rebuilt.

He went home, showered, and used his new cell phone to call his only friend in Gotham (in fact, his only friend ever thus far) and tell her that he was leaving. His plane left early in the morning, and it was on to St. Roch to continue the pattern. His mission is clear, to him, but Gotham was good to him for what it was worth.

He picks up the phone and calls Jane, hoping she's up working on a case. If nothing else, the explosion probably woke everyone in town.

"Hey Jane....it's me." he says.