Now, if one of the people inside were buzzed, there would be a whole new problem. Who wants be left along with a shikkur? Therefore, I say, there is likely a 3rd person there already in which case depending if there were 2 males or females yichud may or may not be an issue at all.
Of course, if all three people inside are buzzed, there may still be a problem because noone inside would be able to be a proper shomer for themselves or anyone else in the room.
There is still room to be lenient if none of the doors had buzzers, all were made of glass and the alcohol was less than 40 proof.Maybe. To rely on this heter, I respectfully submit that you ask you LOR not all LORs subscribe to this heter.