Having 3 choices makes the odds larger not smaller.The keeper guessing the correct side from just 1 in 8 attempts is impressive, but not impossible.
In reality he is currently on a run of 7 without the keeper guessing correctly.
odds of that are 1/128
Actually the keeper has 3 choices to make, so the odds are actually much smaller (cba to work it out)
128/2178 or approximately 5%