Liam has been battling acute lymphoblastic leukemia for 2 years, enduring chemotherapy, spinal taps and everything that goes along with cancer treatment.
PHOTOS: Young boy with illness becomes honorary cop
But it's never dampened his dream to be a cop.
"Because they're the coolest job in the world," Liam said
"He just wants to help people. He's got a really great heart and he's just a wonderful kid," Liam's mom Lauren said.
The nurse at Glendora Elementary where Liam's a student told the school resource officer how much Liam loved police officers and that led to Monday's outpouring of support.
Liam got to participate in a canine demonstration with a police dog named Arrow and got a bird's eye view from the hatch of the SWAT team's armored truck.
What did he like best?
"Driving around in the SWAT vehicle. I also liked the drone," Liam said.
The drone is what Liam called the SWAT team's robot.
"Very emotional, I'm just thankful that our community could come together and the police officers and do something like this for a sick little boy," school nurse Lois Maunz said.
Some of the officers who participated came in on their days off, but they wanted to be a part of making Liam's dream of becoming a police officer come true.
"It touches us because guys have kids. they see we're not always projected in the best way and when kids really look up to us like that, like we're their hero, it's a good feeling for us and we just want to make him happy," school resource officer Ptl. David Belcher said. "Whether they're 7 years old or 57 years old, you take this job to help people and I think we did that today."