Having clicked 10,000 times in about 90 minutes and not getting that medal is pure annoyance.
It feels slower compared to similar click 10k games and this will lead to disconnect and no medal. Fine game with the three other medals but the fourth one is a race against time. If you use more than about 50-60 minutes, the medal stays locked.
Given the disconnect time limit, either the goal should be lower or the game (or just the score) should save so you can refresh and get the medal. Or, in case you actually wanted a timed challenge, put a timer in-game instead of relying on luck based disconnect.