I forgot something, "Universal Acceleration".
Yep, this is the most significant factor for the air to hit the helium.
After the vontainer becomes vacuum, the helium balloon will fall because there is no air molecules that hit the balloon upwards.
BUT when the balloon touch the base, it still stands with balance.
There must be particles other than air -as the balancing factor- that come from under the ground, otherwise the balloon will not stand.