An employee was showing the cleaning contractor where they would be cleaning at the facility. He opened the hatch to a chute. He pulled on the hatch with his left hand and placed his right hand on the lip of the chute to get more leverage. His left hand slipped from the handle and he tried to pull his right hand out of the way, but the fleshy part of his thumb was caught between the hatch lid and the chute lip resulting in a fingertip amputation.