kaomera
Explorer
I think what you need is a way to make the players (and/or characters) want to engage the encounter. If you just randomly lock them in with it, no other way to go, that's no fun. OTOH, the encounter only becomes interesting when the PCs actually try to deal with it directly, and are not just trying to find a way around having to deal with it.The only other thing you need is a way to keep from going back the way they came.
This was how this sort of situation was dealt with in earlier editions. In 1e I had some serious problems with WPL; although it's supposed to be a classic, it was so divergent from how we played the game that the players simply had no interest. The PCs would have found another way around or just gone home before they submitted to a bunch of random rolls to get across the room. Of course, that's exactly what they did each time they faced a combat encounter, but this is no combat encounter...