[Hyperversum]

Some questions about rules (Interrupt Actions, Barriers & possibly something else). SR5
So. I have GMing for a bit of time now after a series of adventures with more experienced players and I am still getting used to all the rules (where I didn't learn everything because the GM was kind enough to check a few things for me while I learned things regarding my PC, a mage) and I wanted to ask if I how I am ruling some things it's RAW or not and, if things are not clear, what's the general consensus.

Interrupt actions.
The Core book says, quoting:
"When a character uses an Interrupt Action, such as Full Defense, he takes an action out of turn, but only if he has enough Initiative Score left in the Combat Turn to pay the price for the action. Interrupt Actions occur outside the normal course of the Combat Turn and do not cost the character their Action Phase (unless they reduce their Initiative Score below 0 with their actions)."

So, if Runner 1 (Iniative: 11) attacks Enemy A (10) in melee with his Katana, Enemy can defend with some Interrupt Action. If he does the Full Defense he goes to 0 and won't act at all in this Turn; if he uses Dodge he goes to 5 and will be able to act.
But what if he was at 9? Could he still use Full Defense or since this action would take him to -1 he can't do that?
Below, in the description of the Intercept action it's said that:
"The Intercept Action allows a character to make a melee attack out of turn. If the character does not have enough Initiative Score left that Action Phase he cannot intercept".
As this isn't specified in the other actions, I assumed that you could always take them and go to negative numbers because they were defensive actions, while Intercept didn't allow to do so because it would be an offensive action.
It's this the case?

1.1) Run for your Life.
This one in particular it's something that bothers me because it's not exactly clear how much movement you can take.
Until now, I assumed that IF YOU ALREADY TAKE A PASS you could use this action to get the fuck out of a grenade/AoE effect area, but if you were Walking during your pass AND you used your Free Action you can't move further than that, as you can't use the Free Action to start running now like you would have done in your pass (because in this way you would be taking two Free Actions in a single pass).
If you didn't use your Free Action before or you didn't act at all but are aware of the threat, you can use your Running speed, as you now consume either your unused Free Pass or you consume the one of your next pass.

If this isn't RAW, does it make sense to you? I did rule so because, well, AoE are punishing but if any gangster with Agility 3 that already moved into cover can dodge my grenade simply through running 12m away faster than my explosion then AoE are useful mostly to take them out of cover and make some ground control. But that's quite uncool, if you ask me.
I also thought about letting move into Running speed if they already took their Free Action by making this action more costly ("Run ever faster for your life").

2) Defense and Barriers.

2.1) Regarding barriers, there is a paragraph defined as "Penetration Weapons".
It doesn't define clearly what's a "penetrating weapon". I would have assumed that only firearms with at least -1 AP were considered penetration weapons due to their higher calibre. This isn't the case, correct?

2.2) Nearby that paragraph there is an example in which the situation is "Defender gets shoot through a wall" and it is stated that in this situation the Attacker will suffer a malus to his attack but the defender doesn't get to dodge (= -6 to your attack, target doesn't get to dodge at all).
Before in the cover section it is said "If the Defender uses a Take Cover action to get behind something where more than fifty percent of the defender’s body is obscured, he gains a +4 dice pool modifier to his Defense roll against any attack. [...] Note that this modifier does not negate the Blind Fire modifier the attacker suffers. Both the modifiers to the attacker and to the defender would apply when firing at a target that is totally concealed (one hundred percent behind cover)".

What I gather here is that if you simply run behind a wall to break LoS you can still get shoot at doesn't get to dodge, while if you use your Standard Action to Take Cover 100% behind a cover, you get the +4 modifier to Dodge and the enemy still gets to shoot you at -6. But does this mean that you roll only those 4 dices on your defense or what? Essentially it's an "automatic dodge with a pool of 10 dices" not dependant on your skills which isn't bad and you get the wall to protect you from low damage attacks, but still it's... strange to me.

2.3) This I am sure it's quite my fault but I will ask anyway because I haven't search enough.
There is a section about a modifier to dodge AoE attacks, but later was published the "Run for your Life" action (let us not consider how absurd is to not publish the "Run for your Life in the corebook) and the general consensus was that you can't use a normal dodge (Ref+Int) on AoE attacks so... it's an error that passed into the final edition of the book?

Bonus question: There is somewhere a list of houserules made from players about messy rules? They are houserules and yeah, I could make my own, but I would really know to see what's the general approach to these things.

P.S. Crap, I just realized it's the first time I posted after a lot of lurking. If I should have posted this somewhere else, feel free to insult me.

[BeCareful]

Let's see if I can take a crack at it:

For the bit with initiative, if you've got 9 left, you can't do Total Defense since you don't have enough for the whole thing. You could parry/block/dodge, get -5, and have 4 left for a whole other Action Phase. I think that reminder for Intercept wasn't to make it an exception.

For Run For Your Life, sure, you can declare that everyone who does that is now Running for the rest of the Combat Turn, the Interrupt action counting as Free for this purpose. This might help if you're handling movement on a map with minis. Also, it's a reason to break up movement rather than just using your entire movement up in the first Initiative Pass. You won't be able to zip up to someone in the first second, but neither will they be able to just take a shot and sprint away. Also, traditionally, grenades are used to flush people out of cover or break up tight formations. You can blow up someone who ran out of movement, or you can aim your toss so their only escape route sends them right into an ally's crosshairs.

Penetrating Weapons vs. Barriers: The way I think of it, "penetrating weapons" count as anything that'll punch a hole through a door and not just smash it off its hinges. So most bullets would count, while most melee weapons wouldn't, possibly save for the Horizon-Flynn rapier.

The Bit About Cover: it's largely a case of who can see whom. If you want a dodge test while someone's blind firing through cover at you (and the cover should soak some of the damage), I suggest everyone putting micro cameras in their ballistics masks/helmets and setting up a group video chat in an AR window.

Finally: Yes, the erroneous penalty and lack of necessary Interrupt in Core was the cause of much confusion, yes there are collections of house rules, which you can find on Reddit or in Dropbox links, and there's even a House Rules sticky here. You can write down ones you like for yourself! Also, no, I'm not going to insult you. Here's hoping my answer to your first post works out okay.