Called by 9611 when the eyes timer reaches 0. If Bilbo is still in room 2 (the forest road) or room 3 (the forest), he has stayed too long: the eyes are shown, the thing drops from above and stings, and Bilbo dies. If he is anywhere else, nothing happens.

Together with AA13 and C6CC, this produces the well-known rule: on entering the forest, wait twice and move on the third turn. The timer is set to 4 on entry; the turn of entry leaves it at 3, the two waits take it to 2 and then 1 (the tick routine is happy each time because Bilbo is still there), and the move takes it to 0 with Bilbo already out of the forest. Wait a third time and the timer expires with Bilbo still there; move sooner and the tick routine sees him gone while the timer is still running.