Again, as Jabbath has observed, it is too dangerous to speculate about anything more serious and that we do not really have concrete evidence.
You pointed out Grisha's behavior for the situation.
I note that this was the first time we saw something active than the much already induced happening in their group outings to the balconies.
And reinforcement that the somewhat "abnormal" behavior is not characterized next and to the moments that succeed as attitudes of "drugged".
See also that everyone was already "high" yes, but because of the drinks that did not diminish at any moment.
Actually the entrance of the last guest was somewhat "disturbing" but I notice that in all the parties there, we always have a central figure where all the others turn.
I thought at first that it was Los Mexicos, but then I changed my vision.
So the central figure would be the last one that arrived later and we can see did not remain or was very present for a considerable time.
Perhaps he will come back in a new opportunity and complete what has been rehearsed.
I just put in check that the balcony is not as "public" as we are led to think. It works yes, as a second and hidden part of the apartment.
This is what VH needs to follow closely and act on its correction( somehow ).
Including blind spots.