perception rolls to notice someone drawing a weapon? (ie punching the frying pan)

[Plane]

There's this cool fight scene in the 24th episode of Transformers EarthSpark (the Battle of Witwicky) between a pair of military women which I'll link for anyone who wants to watch it, but will otherwise describe verbally.

https://www.youtube.com/watch?v=3LAazclvBqo

1) Dot and Karen are exchanging punches and doing a mix of parries and grabbing parries

2) Karen kicks Dot backward, to avoid falling down, Dot grabs onto a nearby handle (the door to the top half of her her refrigerator) and then opens it to hit Karen in the face as Karen lunges in for a followup attack

3) as Karen staggers back briefly stunned, turning to the side, she notices a nearby frying pan on the counter which she goes to grab

4) Dot doesn't notice this because she is ducking underneath the still-open refrigerator door, focusing with angry tunnel-vision on Karen, preparing to launch a combo, and not noticing Karen has already wrapped her hands around the frying pan

5) as Dot throws her punches, Karen pulls the frying pan in front of her face, and Dot lands a one-two combo of punches directly onto the frying pan, instead of hitting Karen's face

6) Dot staggers backward, crying out in pain, and shaking her hands while wincing and looking down at them

Normally if someone was picking up a weapon in plain view you'd probably just assume your opponent would notice, but this seems like one of those situations where because of the circumstantial environment that it would basically be a surprise-weapon-grab and that maybe some kind of situational awareness check is needed.

Otherwise, if you failed it, you don't notice the weapon and operate as if they are unarmed?

I don't know how it works in this case in terms of hurting your hands though, does a successful "Block" by a shield applying the "Hurting Yourself" rules to the person who just punched the shield?

It clearly wasn't a "bash" or anything against the hand (Karen was passively holding the frying pan, not thrusting it) yet even just passively holding up a frying pan as cover DR and having someone smack it (being too caught up on adrenaline to notice it right away) could probably be super-painful and maybe even crippling for the hands if hit too roughly.

It's reminding me of some advanced mechanics for shields and relating blocking/parrying that I might've seen years ago but I forget what they were called.

[RyanW]

If you're willing to play a little loose, allowing players to describe actions that aren't easily covered by RAW and just coming up with a way to handle them on the fly:

Dot's player: Since the fridge door is blocking the line of sight, I'm going to try to surprise her by coming under it and using my punch combo before she has a chance to react.
GM: Okay, but it blocks vision both directions. Give me a DX roll to pull that off.
Player: (rolls) Oh, that's not good.
GM: And a Per roll.
Player: (rolls again) I don't like where this is going.
GM: You weren't quick enough to catch her off guard, and bust your knuckles on the frying pan she managed to grab to defend herself.
Player: Ouch.

More importantly... I just learned EarthSpark season two is coming soon.

[Donny Brook]

There are rules for hurting yourself when striking unarmed so that's the easy part.

Before that, there is the deployment of the frying pan, in particular, when does Karen have a chance to ready it?

At step 3, you have Karen stagger back stunned from a strike with the refridgerator door. I think we need to reinterpret that as she suffers shock and knockback.

Meanwhile, Dot whose turn has just passed, lost LoS on Karen's upper body due to the interposed door.

Karen uses her turn to ready the frying pan.

Dot's turn she uses a Move and Attack. Karen parries with the ready pan. Ow!

Once it is established that Dot lost LoS due to the door, there is no need for or right to a Per roll for Dot to spot Karen's Ready.

[Varyon]

GURPS Tactical Shooting has rules for situational awareness; noticing your foe has just picked up a large weapon should probably give a sizable bonus to your Perception roll, but the GM could penalize you if there was something obscuring your view (say, because you spent part of the round ducking under a refrigerator door). Alternatively, someone who is unarmed should probably have the option of grabbing a weapon they could ready instantly with a successful Fast Draw or similar and using it to defend, probably at -2 to the Fast Draw and subsequent defense (which may be a Dodge if the Fast Draw failed... or maybe failing the Fast Draw means your defense automatically fails).

[RyanW]

Originally Posted by Donny Brook

Once it is established that Dot lost LoS due to the door, there is no need for or right to a Per roll for Dot to spot Karen's Ready.

She wouldn't have seen the Ready, but she could theoretically see the pan when LoS was reestablished. Dot seemed to also be trying to use the fridge door to make a surprise attack. I might call it a Deceptive Attack, and since she is herself blinded, also require a Per roll (or maybe Dodge?*) to pull back when the pan enters the equation.

* I use a house rule that bases Dodge on DX and Per instead of DX and HT.