how to lerp without stopping

i am making an fps with targets that rotate 90 degrees when hit with a raycast

target.transform.localRotation = Quaternion.Lerp(transform.localRotation, end.localRotation, Time.deltaTime * speed);

when i do this it it stops in the middle, can someone tell me how i can make it go to the end of the lerp without having to hit it multiple times?

You are using Lerp with the wrong parameter. Lerp stands for linear interpolation, and as such function, it needs an interpolant with range [0,1] as the third parameter. Using Time.deltaTime will not help you in this case. You need to use either a new float variable that you can increase and decrease as you wish, or Time.time.