in the next room, again it's optional to stick panda towards cini room for more bamboo
Dark Summoner Kazel
this guy can be annoying as hell if you're soloing
with a party it shouldn't be a problem
like any other miniboss, push to a corner and attack
Cini
it's optional to summon panda again if you want extra bamboo
but not necessary if you have bamboo on another side(s)
lure cini to a side that has bamboo near it
kill the bamboo-killers first
bamboo killers are mages and archers (ESPECIALLY ice mages)
you can use the same bamboo you used to trap zakan to trap cini
Lir
Here's the part everyone wants to know
first of all, it will not work 100% of the time
things that are out of your control can happen, such as flying balls
or lir gets stuck against a wall
or she'll use her beam towards wari at the corner, killing panda and bamboo in the process
put panda in corner of secret

put wari in door behind lir

stand near the top-right wall
NOTICE IN YOUR MINIMAP THAT THERE ARE BLUE DOTS IN THE MIDDLE OF THE MAP
the blue dots are bamboo

after battle begins, switch wari to that wall before as lir is about to attack him

go to the top-left wall
when lir is about to attack wari again, put him in that wall

if you haven't noticed yet and i know you haven't because NO ONE CHECKS MINIMAP,
THE BLUE DOTS ARE GONE
which means the bamboo disappeared
keep on switching wari between the top walls until you see blue dots clumped together on the minimap, which means panda made bamboo in secret

it may be hard to see in this screenshot, but blue dots are overlapping each other
in game, it should be easier to distinguish between a single blue dot and many blue dots together
place wari in the corner towards bamboo, or lure lir yourself (though that's more dangerous)
Other Tips
Progressing between rooms
this is a problem i've encountered many times during my 5-10L runs
stand IN FRONT of the arrow
or you better be humping the back of it
there was a time someone was standing in back of the arrow for like a minute and had no idea why we couldn't go
to be safe, IN FRONT of the arrow will allow you to go forward
USE THE MINIMAP
i can't count the number of times i've heard
"where bamboo?"
"glitch done yet?"
etc. etc.
you shouldn't be asking these things if you have minimap open
you can check for yourself
for example:

there are no blue dots
that means that there is no bamboo to glitch lir in secret

purple dots are next to blue dots
what do you think that means?

even though you can't see any monsters on your screen,
if you look at your minimap, you can see where they are
in this case, cini is trapped in the right side

no bamboo is on this side
but if you look at your minimap, you can see blue dots on the other side

purple dot is next to blue dots
zakan is trapped

there are no purple or blue dots
by looking at your minimap, you gain knowledge of the situation
you use that knowledge and act accordingly