In the "The Wyrm turns" quest if one of the heroes stepped on the red objective token can the OL play "poison darts" or "explosive trap" or not.

I thought not because:

A: it is not a door but a " mystical barrier, a curtain of flame " and

B: because the quest guide says: " remove the locked door from the map" and not to open it

So am i wrong or not ?

Please help me!