Never got that close to a convulsion myself, but have felt hypo while cycling. At first feeling of hypoglyclaemia, I always stop, get bike off road and get off bike, sometimes even sit down if it's possible without blocking pavement for everyone else, then get swallow sweets and / or muesli bar(s) from my jacket or rucksack pocket. I have been knocked off bike once by car door, nothing to do with diabetes, just an unobservant car driver, lack of space to swing wider of his door - neighbour came out with a clean teatowel, ambulance staff took me to A&E; swapped details, driver & his family took my bike to repair shop. I have picked up drink cyclists a couple of times, one with non-functioning brakes, which probably had more effect than inebriation, looked after then until ambulance arrived and took them & bikes to A&E.
So, STOP & EAT SOONER!