You don't want to call Telus, you want to call a government regulatory body, because if you don't have a cell plan, the only way you'd get 911 access is if the government requires providers to provide it. And Telus customer service sure won't be likely to know the answer to your question, let alone provide information to you... as you say, those folks work for Telus and if you don't have a plan with Telus or want to buy a plan for Telus, they sure don't see you as a "customer" worthy of "customer service"!
But... wouldn't you lose your phone number if you didn't keep your plan? And would your phone even pick up a signal? What happens when your phone is charged up and you open it... does anything happen? If not, can't see how you'd get access.
Why not go with a cheap pre-paid plan? They're popping up all over and then you can be sure you'll have a working phone when you need it. That is, if you remember to charge it up! My mom is one of those people who ONLY wants to use her darn phone for emergencies and she never remembers to charge it up or carry it with her anywhere.