I have a good option here: Dairy.
Basically, your body can only produce so much Lactase (the thing that breaks down Lactose) at a time. Lactose intolerant people barely produce any Lactase, which is why eating a tiny bit of cheese is OK for them, but they'll explosively shit themselves if they have a glass of milk.
Anyways, you have a lactase limit, time to find it. An added bonus of this strategy is that your options are a bit more varied: You can load up on cheeses, milkshakes, cream puffs, cheesecake. Regular old milk has the most lactose though, so if you want to shit yourself plentifully and violently, bring a ton of that (and whatever other foods you want, the milk will do the work here). Just don't try and chug a whole gallon of milk in under 20 minutes, you'll vomit because it will dilute your stomach acid until instead of digesting it, it'll curdle in your stomach.
Doubt it. I think this guy wants control of Russia.
I strongly advise you not to give Prighozin the benefit of the doubt- he's a HUGE Nazi, and has the tattoos to prove it (plus he literally named Wagner after... well, Wagner. Hitler's favourite musician).
Best case here is mutual destruction of russian leadership.