Has anyone who is not in Slytherin been able to get in the Slytherin commone room. If so how did anda do it?

anda have to make the Polyjuice potion.

anda used to have to brew the Polyjuice Potion first.
Now, all anda have to do is go to the right moment and zoom in. anda pass through the dinding and are in their common room.