A few questions regarding explosives

[SamuraiZero]

There have been a lot of questions regarding grenades, and explosives in general in my group, and since a lot of the questions for grenades also fall under explosives, I would like to keep this discussion about explosives, and set charges using the Engineering skill.

What is currently known: Explosives count as the same price, effect, and weight of grenades. A detonator can be used to prime and detonate explosives using the engineering skill to set a charge. An explosive charge that has been successfully set on a stationary object ignores half of the objects hardness.

So here are the questions:

What is the DC of a set charge? A grenade is stated as DC 10+half i.level+dex, so do Explosives have the same DC?

If I wanted to set a breaching charge on a door to blow it down, then what is the typical health/DR of a door that I would need to bypass?

Going off the last question, can I set multiple charges to a singular detonator, and detonate all simultaneously?

As with the last question, could I set explosives to detonate the door, and a single flash grenade to blind those behind the door once detonated?

What happens when a creature swallows an explosive charge, and the charge is detonated? Does it still get a reflex save? Do the creatures around said creature still take grenade splash damage? Does the grenade do increased damage for being localized entirely within the stomach of said creature?

An explosive goes off (lets say a shock explosive) near multiple enemies who also have explosives on their person. Does the shock detonate those explosives, damage/destroy them, or have no effect? Is there an explosive that could potentially have an effect?

What's to stop a player from spending credits on multiple level 1 fragmentation explosives, daisy chaining them to 1 detonator, and then creating a satchel charge that is cheaper, and just as effective as higher level grenades? ie. Player A spends 2000 credits on 50 Frag I grenades, he then spends 50 minutes setting each explosive to a single detonator, and puts the entirety of the explosives into a single backpack (essentially creating said satchel charge)
and then uses said backpack to turn a group of enemies into pink mist.

[Over 9000]

I see the DC to set a charge as the DC of the "Arm Explosives" part of the Engineering skill, but others may disagree.

Harness / HP apply depending on the doors material; a door made out of steel has 20 hardness and 30 hp per inch of thickness. You may get additional modifiers based on the type of explosive you're utilizing or determining weak-points in the object.

The GM may have to rule on the next few questions, but I can provide my interpretations:

You probably can't simultaneously detonate objects and expect a similarly large effect.

You should be able to tie multiple devices to one detonator, but the effect of utilizing it would only affect one explosive at a time; and the rules imply one explosion does not trigger another but destroys the object.

I don't think you'd be able to blind creatures on the other side without the effect happening after the door was breached.

If a creature swallowed a grenade, I would say they don't get a save and potentially receive maximum damage but the rules don't support this.

Above keeps players from daisy chaining explosives. If you're looking for more effect, you'll have to utilize a higher level grenade.

[Vexies]

it's something that has recently come up in our campaign as well. My PCs wanted to create a breaching charge for a door. I see they mention receiving modifiers for determining weak points and all that, dont see anything about modifiers for type of explosive though. The thing is as far as I can see they never bother mentioning what those modifiers might be. Anyone have a guess? for the time being I ruled that after the engeering role is made to locate a weak point the charge ignores an additional 1.5 times hardness ignored so a charge set on a 20 hardness steal door would ignore 15 harness rather than 10.

[SamuraiZero]

Over 9000 wrote:

I see the DC to set a charge as the DC of the "Arm Explosives" part of the Engineering skill, but others may disagree.

To clarify, I wasn't speaking about the DC to set the charge, but rather the Reflex DC for creatures in the charges blast range. It didn't seem to make sense that Dex would be added to a stationary charge, but I thought I'd ask for clarification anyway.

Over 9000 wrote:

The GM may have to rule on the next few questions, but I can provide my interpretations:

Unfortunately, these questions came up in Starfinder society. I was hoping to get clear ruling, or at least grab the Dev attention so that they can clarify. While I agree with most of your solutions, I cannot simply point this out to GM's, and would prefer to have something official rather than having to bog down the game every time I want to blow something up with my sapper.