Elevator CCTV installation complicated task for physical wiring laying due to movement of LIFt. using Wireless device elevator CCTV installation easy and long-lasting as well as maintenance free for a long time. so you can use a wireless bridge to connect CCTV camera inside elevator and monitor it from a different location where NVR installed using the network. However i have find a simple understanding elveator CCTV installation manual in this website you can read it to understand the way to <a href="https://techtrickszone.com/2019/09/07/how-to-install-cctv-camera-in-lift-using-wireless-device/">installation of CCTV in elevator </a>.
The camera only showing black and white color can be due to mode selection. you can switch PAL, NTSC mode using CCTV camera small reset switch. You can follow step by step solution for CCTV camera only showing black & White Here