Sequence 4 - Unnatural Selection: Assassin's Creed: Syndicate Walkthrough
Jacob continues his search for the creator of Starrick's Soothing Syrup by tracing it to its distillery. So as we start with the Second part of the Sequence 4 - Unnatural Selection.
You'll notice a guy is trying to snoop inside the Distillery and wondering what's inside it. As the guards(thugs) arrive he quickly manages to hide inside the hideout.
You Job is to kill all the guards and open the locked Distillery's door. The man inside the hideout then comes to you and introduces himself that he is a Gentlemen. So get him inside along and start examining the area until the Gentlemen sabotages one of the Gas pressure Valves.
Now Go Upstairs and sabotage all 4 pressure valves also you have a side objective to kill everyone upstairs with the gas only. So make your move fast, it's pretty tough to kill everyone with gas so make you own luck. After sabotaging all the valves you must escape the building.
Once you've done sabotaging the valves meet this Gentleman outside where he will introduce himself to you. His name is Charles Darwin, then provides the information about Syrup samples which were sent to Lambeth Asylum and ask you to join him to continue the investigation.