Her silence was expected, on his end anyway. This was the part where she was thinking up a very polite way to tell him that she wasn't interested like that. The words 'you seem like a great guy, and would be a great friend but...' were going to slip out of her mouth next.
Then he would say it wasn't a big deal, and he'd still be willing to take her out. On a friendly type thing instead. After which they would talk if they ran into each other, but neither would make phone calls.
So Ted was stunned into his own bout of silence when he heard her acceptance.
"Um." He snapped himself out of it. "Yes, of course. Would you like to meet me there at about 7? I would offer to pick you up, but I don't have a car here. I suppose I could arrange for a cab to get us both."