Tomoe goes to do that but strangely there is no guard at the building and she can just walk in.

Tomoe cautiously enters the building. 

Inside the building are a bunch of people, obviously from rock bottom financial status, shambling about like zombies. These guys are stoned out of their minds. There are a few Rat Livers who are also stoned. It seems unlikely that the boss will keep his gems here. They must be in his room... But which room is it?

On the ground floor, you notice that there are a grand total of 5 doors, not counting the main entrance. Considering the entrance to be on the east wall, there is a hall that is 20ft wide going straight west. On the south wall of the west hall are two doors spaced fairly apart. Before the west hall starts, there are also 2 doors on the north side and 1 door in a niche on the south side.

Are any of the doors guarded ?

No

I'll start with the 1 on the south.

Going to the south, you open the door and notice that it's a store room. It's mostly full of cleaning supplies. Roll DEX

Save or pure dex?

Save

DeX save 25

Tomoe manages to jump out of the way just in time to avoid an avalanche of stacked cleaning supplies. She hears someone say, "What was that?". One of the two doors in the west hall opens and a half-elf with a short french-cut beard steps out. He eyes Tomoe and says, "Who are you? You don't look like one of these junkies."

No, I'm the new janitor. I just wanted to clean the place up so the junkies had a nice place to be.

The guy eyes you suspiciously. Roll deception vs. Insight: 17

Deception 14

The man squints his eyes and says, "Thought you could pull the wool over old Raxor eh? We Rat Livers don't hire janitors. Get her!"

From the door where the man came, two more thugs show up armed with clubs (no armor). Raxor himself has leather armor and a rapier. Finally a 3rd gang member appears, this one drugged out of his mind.

Initiative:
Tomoe - 14
Raxor - 6
Rat Liver1 - 6
Rat Liver2- 10
Stoned Rat Liver (Disadvantage on everything) - 15 (Dis: 6)

Your turn

Tomoe shrugs, Worth a shot. Tomoe pulls out her shield and hand crossbow and shoots at Raxor.

Attack: 22 Damage: 8

she retreats as far from her assailants as possible.

With one shot, Raxor goes down. The two other guards look at each other and... 18

They decide to take the tactical approach and take cover behind the walls of the niche. To get out of here, Tomoe must pass by them. Meanwhile the stoned guard moves in but is unable to reach Tomoe.

Your turn.

(For theme, im going to call my rapier something Japanese. But its a rapier, if that's alright with you.)

Tomoe drops hand crossbow and draws her sword, she closes the gap between her and the stoned guard and goes for a non lethal stroke.

Attack: 7 Damage: 12

(Yeah you can name your Rapier something Japanese)

Tomoe knocks the guard out with a swift blow to his neck from the blunt side of her sword. The two other gangers take this chance to move in and attack (Readied Action)

[0 Movement for this turn to the gangers but that's not important since they are in melee range]

Reaction attack1: 6 Dmg: 4
Reaction attack2: 12 Dmg: 3

Action attack 1:3 Dmg: 3
Action attack 2:14 Dmg: 1

With a combination of her shield and her swordplay, Tomoe manages to block the barrage of attacks, only getting hurt on her shield arm by a particularly strong strike hitting it from an angle.

Your turn.