Your on a mission with Percy and Grover currently being chased by a monster through the gateway arch, Percy had been poisoned by something and wasn't strong enough to fight

"You guys go ahead I'll fight, go and don't stop running"

You said and Percy wanted to stop you but instead took out his sword riptide

Percy:"Wait.."

Percy acted as if he was gonna give you riptide but pushed you out the door with Grover locking himself in with the monster