One of the PCs in my game ran out of air in is diving suit, but I can't find any information on drowning or suffocation. I hit Arsenal and the 20E 4E book, but can't find them anywhere. Help? I need this for next time the PCs risk drowning.

… They die? The rules are on SR4A p137. You didn't try searching for 'drown'?

aren't underwater, deep sea, and other extreme environment threats(like space and deserts) covered in the back of Arsenal?

away from books at the moment, can't look it up for you, but I think they're in that book.

Yes, Udoshi, but nothing about drowning. Cuz it's in the core book, p137.

The rules seem a bit off for me. 'Course, I grew up around Hosers, and we all know how well they can hold their breath.

16 Turns seems pretty generous, plus 2-4 more based on your Swimming + Willpower.

Which is pretty much 1 minute.

And after that you get 1 box of stun damage each round. So you have another 27 s for everyone before something serious happens. Given the fact that you get this time regardless of circumstances I find it a pretty good approximation. Even though I can hold my breath almost 3 min under good circumstances, this time drops rapidly if I start after exertion or simply after exhaling.

And most people have much shorter times, under the best circumstances. It's more than generous.

Do you think strangulation is faster, or is that just reflected in subdual combat?

Sheesh. I looked everywhere except swimming. Thanks for the heads up. Hmm. 16 combat turns. I guess that will do.

Strangulation is much faster.
About 3 secs. You directly cut the bloodflow to the brain. So after 3 secs you are black out/unconcious.
(The point is, it is quite hard to get the hold right.)

Well, I had the pleasure of bloodchoking someone recently. It felt like an eternity till they passed out, but I'm pretty sure I did not apply the choke properly.