Kirks chute was fine, it retracted correctly, and could be reused later. Had they stayed on the drill they'd have been fine too, but Sulu fell off. Kirk dived after him, caught him, and pulled his chute. The combined mass was too much (they were likely at terminal velocity at this stage), and Kirk's chute broke off immediately.
What they could have done with is a pair of gravity boots to get back upto deck 89.