Warhammer: Vermintide 2

Below is the link for a full run through of the level. This will show you how to speed run the level on Legend Difficulty in less than 10 minutes and the best part is no fighting skills required.

The only character I tested was the Handmaiden but I did test several variations of potions for use at the end which I will discuss later.

Handmaiden Build:
Talents: Lvl 5 Wraithwillow (Increase blocks and pushes by 50%)
Lvl 15 Gladerunner (Increase speed by 5%)
Lvl 25 Gift of Ladrielle (Disappears for 3 sec after dash) The benefits of this one tremendously outweighs Handmaiden Grace, increase cooldown by 30%, because it is crucial in running the verm around the burn the food room while waiting for the escape path to open.

Equipment: Charm Trait: Decanter (Increase duration of potions by 50%) MANDATORY
Trinket Property: Increase movement speed by 5%

TIPS for the speedrun. Practice a few times on Recruit and take note of where potions and health are along the path. The path I use in the video is the most direct and shortest of routes. And, get practice on the final bridge run.

Bots are only needed for decoys to slow down the horde behind you and take out specials. So, if you can revive them, do so. But if you hear clanging of stormvernon on your tail, its not worth the risk, skip him and try to revive the next one.

Bosses, ignore them and keep running. The only one that kills the run is the troll as he will leave a barrier blocking the path. If a boss spawns on the first half of the run, it will go into the building with you where you need to burn the 3 food stashes. Just keep running clockwise, and dash when they swarm infront of you. Use the stairs on each lap, there are 3 sets of them in this room. Do not revive bots in this room until you are ready to leave because they will cause pileups of verm which screw up your clockwise circle in the room. A bomb at the start of this segment greatly reduces the amount of verm to kite through and is also great to finish off any specials that may have followed you into the building from the start of the level. After they die, no others will spawn in that bldg.

Finally the Bridge: (stay on the middle line as much as possible)
I tested several variations of potions and found that these 3 combos all work: (one that you find and carry on you and the second is location midway on the bridge)
Speed potion + Speed potion: My least favorite because you run so fast that the floor doesn't collapse until you are already standing on it.
Concentration + Concentration potion: This one is the most friendliest one to use. First, which I didn't realize until recently is that when you drink a bottle with the double potion charm, you can do up to 8 dashes in a row. Since your speed is slowed down, the floor falls before you reach it allowing you to slightly adjust to the right or left and then dash. Do this at each segment after you see which side is collapsing.
Speed + Concentration potion: Which is what I got in the video. If you are standing directly on the middle line, either side of the bridge can collapse and you will not fall, it is just tough to do when you are also combining in dashes.

This achievement is individual, meaning if a team member gets it you won't get credit for it.

This is for completing the finale of the Pit, on legend, in under 30 s, there are a few ways to go about this but I'll give the way that worked for me.

Firstly you need an item that has the increased potion duration trait, these only appear on orange or higher rarity and can be rerolled until you get the right one.

Secondly you need to play as a character that has a dash and preferably movement speed in their talent tree, I like the handmaiden but the slayer dwarf is good too with the movespeed buff on leap.

The idea is that you use a speed or concentration potion, so you can repeatedly dash or run to the end. If you have a bot with a potion they can hand it to you if you are near enough (e.g. drinking it before pulling the lever) so you can get double to amount of potions that way.

The only thing to note is that the floor falling seems to be random, so take care while dashing on the wooden parts as if you are too fast you can easily kill yourself instantly.

Any comments or suggestions let me know.