By Philiana Ng
Adrian S. Burrows Sr./NBC
With only a handful of episodes left before the
Chicago Fire season 9 finale, you can bet the drama is about to ramp up even more. Executive producer and showrunner Derek Haas revealed that they're "going big" for this year's season closer, which officially began filming in Chicago on Tuesday.
"We're going to have one of these gigantic last 10 minutes that drive our audience crazy," Haas tells ET. "I definitely enjoy building up to what feels like a giant ending to each season that makes audiences -- because you know they have nothing until October -- so you've got to have them thinking about it all summer long and yes, I do take pleasure in that."