Surprisingly, it often takes effort to find a sales assistant who can check whether there's available inventory in the back. I usually leave if it takes more than a couple minutes to get help. So, the sales team needs to balance being available while not being in my face or making me feel rushed.
If I've gone to a store with the intent to buy, the staff should be able to close the deal, especially if I'm asking for a specific SKU. With a simple binary question, it's reasonable for me to expect a quick answer. So, help set my expectations if you're being pulled in multiple directions. I shouldn't feel the need to resort to asking multiple people for help because I'm unsure whether you've forgotten about me. Letting me leave in this situation is a clear missed opportunity.