// If it's on a stair, make it leave the level.
            else if (mon->travel_target == MTRAV_STAIR
                && mon->x == mon->target_x && mon->y == mon->target_y)

            // If it's on a stair, next to a trap, or can submerge where
            // it is, make it leave the level.
            else if ((mon->travel_target == MTRAV_STAIR
                    && mon->x == mon->target_x && mon->y == mon->target_y)
                || (mon->travel_target == MTRAV_TRAP
                    && distance(mon->x, mon->y, mon->target_x,
                                mon->target_y) == 1)
                || (mon->travel_target == MTRAV_SUBMERSIBLE
                    && mon->x == mon->target_x && mon->y == mon->target_y
                    && monster_can_submerge(mon, mon->pos())))

            // If it's next to a trap, make it leave the level.
            else if (mon->travel_target == MTRAV_TRAP
                && distance(mon->x, mon->y, mon->target_x, mon->target_y) == 1)
            {
                _make_mons_leave_level(mon);
                return;
            }
            // If it's in a submersible place, make it leave the level.
            else if (mon->travel_target == MTRAV_SUBMERSIBLE
                && monster_can_submerge(mon, grd(mon->pos())))
            {
                _make_mons_leave_level(mon);
                return;
            }