How is this possible?

I am usually not one to complain about XP farming, but I searched up one of my competitor's profile and realized they were getting 72XP per 8 seconds or so. This person was able to rack up more than 8000 XPs to climb to the first position in fewer than 30 seconds. Obviously they are using a triple XP multiplier, so 24 becomes 72, but I don't get how they are able to complete anything in 8 seconds.