If he was holding the manual card punch I used at school he would have needed both hands as it was a substantial chunk of metal. That was essential as there was a queue of 30 of us for two punches so you tended to pound things out (in EBCDIC if I remember correctly) as quickly as you could. The cards were for an ICL 2900 Series. At the end of the class the teacher would take our bundles and drive them to a local government office some miles away. We’d receive the cards and the printout (132 column, green and white striped) at the start of the lesson the following week. When we switched to a (single) Commodore PET (real-time computing!) the competition was even more fierce, until some well-heeled pupils acquired their own ZX81s.