This part is from the script for the enemies. This script gives the enemy health, allows them to shoot and get hurt, and allows the player to hurt them and when their health is below or equal to 0, the enemy plays a death animation and all the scripts on him are turned off. I had a problem with the enemy not dying properly as when he died the scripts were still turned on even though I disabled them in the script. This took a while to figure out as I spent a long time trying to fix it but I have fixed it now so when the player kills the enemy, he now dies and all the scripts are turned off.
Here is the new model for the arch which is a lot higher poly than the one I originally had.
Here is the broken version of the arch in Unity as well as the unbroken one in the background.
I also removed the ability to damage yourself by pressing E as that was temporary.