Jared wanted revenge against Eli, a local laywer who sent his brother to jail so he showed up at Eli's wedding reception with a homemade bomb. He hid the bomb in a backpack and when all the party guests were inside he stashed the backpack under the porch with a timer to go off in a few minutes.
Maeve and Knox knew Jared was up to something so when they followed him and saw him stash the backpack under the porch they knew he had evil intentions. After watching him drive off they pulled the backpack out and realized that it was a bomb so they immediately started freaking out.
Knox grabbed the backpack and sprinted away from the building where the wedding reception was happening because he knew the bomb would go off any minute. He hurled the backpack as far as he could and then sprinted back to take cover with Maeve who stood there in shock.
Knox and Maeve dove to the ground and covered their heads to take shelter just as the bomb exploded. Frightened guests emerged from the wedding reception to see the remains of the backpack in flames and they all commended Knox for his bravery.