If you haven't already done so, be sure to read the section on Haplochlaena spp. in the new "Cephalopods" book from TFH by Colin Dunlop and Nancy King. There's some very relevant stuff in there you need to know. It's also a great book simply to read for fun.
Anyway, the venom is tetrodotoxin, and this causes voluntary muscles to stop working. The heart continues to work, but breathing may not, and survivors get through the ordeal by being given breathing support on the way to the hospital and being hooked up to respirators once there. The authors note that they're conscious through the whole ordeal! Make darn sure you have the type of venom written down somewhere that everyone can read and knows about, so if something happens your family can tell the paramedics what's happened. This is very good advice for all types of venomous fish as well, and I recommend that people keeping lionfish and shark catfish do the same thing.
Oh, and remember, this isn't just about you. Children are as likely, if not more likely, to get bitten when playing around the tank. As/when the octopus escapes, your family should know they shouldn't pick it up and put it back in the tank.
One of the things about the bite that is most alarming is that it doesn't work instantly and the bite itself may not even hurt; it's possible to be bitten without actually knowing it! Symptoms such as dizziness set in after a while, at which point it may be too late to get medical help.
For what it's worth, the lifespan of these species is quoted at 6-8 months. Obviously if you collect an adult specimen, it likely won't live for more than a fraction of that time even under the best of circumstances. On top of that the species ships poorly and doesn't adapt well to captivity.
If I recall correctly, Colin Dunlop hangs around the TONMO forums a lot, and this is one of those times where a recommendation to go to another forum may make sense. Since he's kept these octopuses and written about his experiences, he's probably the best person to speak with about their care and requirements.
Cheers, Neale