Because 3/4 students are weeded out. And at UF, 4.3/ 1400/31 is just the top 25% threshold.
Except premeds are usually pretty competitive…and, in order to remain premed you must be in the top 10-20% or so in every class you take. Therefore you need to be quite a bit above the top 25% threshold to have a shot not to get weeded out.