I made this little tutorial game for showcase:
There is one example for how it always works; one only for if you are already in a room (e.g. if you have teleported there or if you start the game in that room); and one that works fine for triggering a cutscene when entering a room... Here they are:
For the solution that always works (Example House 2):
For this solution, you have to teleport the player inside of the event, not per door... Here it's very important that the door in the room you want to lock the player in is behind the invisible actor! If you connect that door to teleport you back outside though, you will be immediately teleported back - which would look like you didn't even enter the room! So don't do that!
For the solution that only works if you are already in that room (Example House 3):
The main difference here is that it's a bit faster to create than for the solution that always works - and you can connect the doors directly! But as I said: it only works if you are already in that room (if you enter the room from outside, you are stuck in the inside room!)
And finally the solution, that you propably meant (Example House 1):
This seems to be the first thing to do if you want to create a locked room... It does work, but its best for a cutscene when you enter a room. Since you must put soemthing under 'if hero lacks token' or 'if hero has token', what you put there will immediately be triggered! What means: if you enter the room, there will always have to be some text or another action! You may be able to avoid this by simply just leaving it with the action '[door] becomes inactive' - in that case though, when you walk down to the door again, it will simply do nothing!
...So be aware that if you don't want an action to immediately trigger after you entered a room - or if you want to give the player a warning that you can't leave the room - it's best to use some of the examples mentioned above!
Okay, that was it, I hope that helped,
(Sorry, I had to edit this a few times! This is the final version though! ;))