This scenario is an interesting read, and it is not a bad script for a Cthulhu-themed movie. Unfortunately, it is probably not a good scenario to run as a game. Alas. I'd only recommend it if the DM is either willing to use the PDF as a starting point then make major modifications to the scenario, or if you have players who are big fans of action & combat.
The fundamental issue is that there aren't really any points in this scenario where the players get any actual agency to make a decision, to choose whether to trust someone, to understand a situation and make the right call. The only way that you can really derail the scenario is via doing well or poorly in combat, and, well, that isn't really what Cthulhu is usually about, right? It'd certainly be very anti-climatic, IMHO, to have the party slain in straight-up combat against normal humans with guns. There are games that are based around small-squad tactics which you can play instead if you want to do that that have much better systems than Delta Green does for handling combat situations and making that interesting and gripping. The PDF is rather blase on this point, lightly recommending that characters with non-combat oriented investigators can simply take over US Army NPCs provided in combat. I don't think "drop your current characters and play War in Afghanistan Simulator with these soldiers" is what most people are expecting here.
Anyway, I don't want to spoil the scenario too much, but there's likely to be one combat on the way to Kali Ghati, then another combat at Kali Ghati. There isn't really a good way to avoid these combats short of "roll lucky" or "abandon mission". There isn't a solution or a way to fix things other than shooting your way out. There isn't a way to usefully earn the trust of the opposition. This is fine in Dungeons & Dragons / Pathfinder, not so fine in Cthulhu IMHO, whose system for combat is not great. Play to your strengths, not your weaknesses!