As I dive with AI, I'm not bending my arm around for anyone to look at my DC. If they don't understand the technical diver way of indicating cylinder pressure, I'll give a signal they are sure to understand. If I'm diving within the parameters of the dive in terms of time, the fact that I'm blowing bubbles is all they need to know.
In every dive boat I've been on, the captain has briefed us that he'd be banging on the ladder in the case of an emergency. I'm not cutting my dive short if I'm diving within time agreed parameters, unless it is the DM. I'd ignore some rando.
We could do the mash the inflator button experiment we discussed in the other thread.