for shortcut, you can talk to the npc for an instant get in for 1k c$ and 5 pieces of amber
but you don't have any right now,
so, you will have to access there first via beating pitaro ruins
after you done so,
take up all 6 quests from the npcs for the usual (they reset daily)
which you should just kill everything in there to finish up the quests
b1f, radar jammed and very mazy
these arrows you see leads you to the gate (of course you have to go the other way round)
so, heres a map done by someone , get all 3 yellow stones and proceed to the gate as shown on the map
and not to mention the mobs in there drops centusion, vanguard axer, dug driver, both garula birds, daemon parts, and also weapons like twin blaster, sonic blade and even heavy artillery gun
however, their stats and weapon force are weaker than their mt/gacha counterparts and best of all, they are all tradable
b2f
just look for the gate
the gate shown here sends you back to the start of b2f
for the right gate just go straight as shown
then go down
and proceed
b3f
you will have to go through this 4 times
each time will have different enemies
head off to the gate for 4 times (and of course, kill off the mobs for the quest.)
2nd time
3rd time
4th time
and after the 4th time
just enter the gate to proceed to the next floor
b4f
just get rid of the surrounding enemies first
and after that move to the middle or so to trigger the field boss to spawn
take that out for it to drop the stone, and pick up the other 4 on the corners
b5f
there are 4 paths by stone color (red, purple, yellow and blue)
which you should take out the enemies
and open the gate with the stone, but however, you can only enter 1 gate
b6f
nothing, whichever route you pick, you will always be in the same floor
and of course the same boss.
b7f
boss: king yamma X 2
yellow is immune to electric and blue is immune to beam
and both of their shotguns hurts alot if close
and they blew up.
you can also get yamma parts2 which is slightly bigger version of the original...