I have several questions about the use of the flashbang grenade.
- First off, the required materials and complexity of such a device. Looking at flashbangs on Wikipedia, they require a specific manner of construction to contain the explosive side of the grenade while still allowing the light and sound to escape. Plus they require specific compounds; "a pyrotechnic metal-oxidant mix of magnesium or aluminium, and an oxidizer such as ammonium perchlorate or potassium nitrate."
I don't imagine such materials come cheap in this setting, if they can even be found outside of a major city that can devote manpower and resources to mining and production.
- Second, the idea that Johnathan just happened to have the flashbang on hand. There's no mention of him having built it in a previous post, and in all honesty that doesn't work for me. If you don't mention you have specific items on hand that aren't your usual weapons and equipment, then I'm disinclined to believe someone can just whip out the right tool for the job at the right time. No character should be able to react perfectly to every situation.
- Third, the use of grenades as a whole. Mechanists build gadgets and robots; no mention of explosives in their descriptions. If you want something to go up in flames, you call a Pyromancer. If you want an explosion with special effects, I think an Alchemist is probably the better bet, and even that should be at a minimum of Weaver rank due to keeping unstable mixtures on hand until they're needed - which could be in the first mission or not for the better part of a week.
- As an aside, I note that Johnathan took a hit to the face from a shadow whose owner was between Mage and Adept in rank and didn't even flinch. You are not invincible.