T6.1

There are wood planks along the floor of the tunnel and you can hear a faint trickle of water echo around you.

The planks cover up loose holes in the floor, stepping on them keep you from falling. If not specified, walking along causes the floor to crumble from your weight.

The floor crumble beneath your weight, you try to maneuver to one of the wood planks that seem stable.

Reflex DC 20 to avoid falling. 1d6 falling damage into water below

''You fall into water far below, thankfully it is deep enough that you don't hit the bottom. The current isn't swift but strong, carrying you into (the previous/another room).''

From R6
''You enter a rocky tunnel, that levels off from your incline. As you go along the air cools in temperature and you hear a stirring up ahead.''

From R12
You enter a rocky tunnel, as you go along the air warms and the walls begin to glisten with moisture.