I called to ask the hours to come in for a blood t...

I called to ask the hours to come in for a blood test. The operator said the lab is open till 5 PM. I asked (just to make sure), "So as long as I come in by 5 PM, I'm good?" The operator says, "No."
Long pause...
I ask, "What time to I need to be there and still get my blood drawn?"
Response, "The lab is open until 5 PM."
Another long pause... "So... when so I need to come in?" "Oh, you have to go through admissions." I asked, "Can you give me a time?" Oh, come in by 4PM."