The IP was assisting in the operation to close the BOP doors. As the door was closing the gasket slipped. The IP gave the signal to stop closing the door via radio to stop. On hearing the signal the Toolpusher at the control panel, put the control lever to the stop position. Due to the residual pressure in the control lines, the BOP door continued to close for a few seconds. During this time the Injured Person placed his hand between the BOP door and the BOP body in order to replace the gasket. The closing door trapped the IP’s hand between the BOP door and body. The IP was examined by the rig doctor and it was decided to send him to a hospital for further examination and precautionary x-ray. No broken bones or muscle damage were sustained and the IP returned to full duty. The case was classified as an MTO.