Flight Instructor reported confusion surrounding verbiage instructing a go around resulted in a runway excursion and minor aircraft damage.

Narrative

I was conducting a standardization flight with a new hire at ZZZ1. While conducting a short-field landing on Runway XX at ZZZ the pilot flew high to avoid power lines near the approach end. As a result we were approximately 10 kts. fast going into ground effect at our aiming point which resulted in landing later than our touchdown point. Realizing we still had too much energy I told the pilot flying to add full power; however there seemed to be some confusion between us and power was not added until a few seconds later when I stated it again. In the confusion I believe the pilot flying had the brakes held as full power was added which did not allow for us to gain enough airspeed to rotate and ended up over running the runway into the cornfield at the departure end. Once realizing we were not going to be able to get airborne I instructed the pilot flying to pull the mixture to idle cut off and I turned the magnetos and master switch to the off position. When the plane came to a stop me and the pilot flying both exited the aircraft safely and made sure we were both unharmed. The airplane sustained minimal damage and after a visual walk around I believe it was just the propeller that was affected.Prior to the flight both me and the pilot flying were very familiar with the weather conditions and had just flown an Aircraft Y the hour prior to this flight and I verified the weather conditions using foreflight imagery to take note of trends and did not see anything of concern. There was an occasional light chop below 3;000 ft. with a ceiling that was around 3;000 ft. MSL that was becoming scattered. There were light winds out of the northeast. Upon reaching ZZZ we overflew the airport to enter 45 degrees into the left downwind and took note of the wind sock that was indicating about 020 at 5 kts. The windsock confirmed our decision to use Runway XX as it's what the winds favored. The weight and balance was calculated prior to flight and ensured we were within the prescribed envelope set by the airplane's AFM. I do not believe this to have played a factor in the aforementioned event. We also calculated our take-off and landing distances as prescribed in the AFM of Aircraft X the airplane used for this flight. It was found that we had enough performance to safely take-off and land on Runway XX. The pilot flying was also a flight instructor that had just gotten their certificate in an Aircraft X which I believe gave me a false sense of security and resulted in me allowing the situation to progress further than I would have flying with a non instructor pilot. I believe this perception of thinking they will execute the go around without being instructed was a contributing factor to why I did not call for one sooner. Another factor that I believe may have contributed is my use of the terminology 'full power' rather than stating go around. In the moment I did not catch my error may have caused confusion between me and the pilot flying about the action desired. In terms of human factors I think seeing the end of the runway approaching may have caused the pilot flying to apply brakes while full power which contributed to the attempted go around after the balked landing to fail. Going forward I believe I need to actively mitigate the perception that flying with another instructor is any different than flying with a student. Had I been in the mindset that I am the ultimate PIC I may have intervened and taken the controls rather than just telling the pilot flying to go full power for a go around. As soon as I noticed we were high and fast I should have called for a go-around to have them make a more stabilized approach. I also should have conducted a more thorough pre-brief involving the setting of roles for the flight and who had final command over the aircraft to minimize confusion when a situation like this arise.