"Maya! Please! Wait!" he cried. But it wasn't until the next intersection that he finally caught up with her. Unwilling to let him see the tears in her eyes, she initially refused to face him.
"Maya, I didn't think he'd ... I'm so sorry ... I don't know what's the matter with him," Ethan stammered, still coming to terms with the fact that, in the course of a few seconds, the sense of hope and excitement he felt at the possibility of helping his grandfather had turned to such shame and anger.
"It's OK," she replied, gathering her composure and turning to look him in the eye. "He comes from a different generation. They don't mean anything by it."
And it wasn't the use of the word gwei-mui that had hurt her - that was a common expression in Hong Kong - it was the intent behind it. "You should hear how some people talk about foreigners in Britain," she continued.
Ethan knew she was just trying to protect his, as well as her own, pride, and at that moment, as he took her in his arms, he realised what a challenge it would be to justify her faith in him.
Mr Wong had entered his friend's shop to find out what was wrong with Ethan, but now it was Grandad he regarded with incredulity. "You asked him what he was doing with a gwei-mui?"
Grandad stared back, defiantly. "Well ... it didn't happen in my day."
"In your day, people wouldn't marry a girl if she came from a village on the other side of the hill, never mind the other side of the world," Wong told him.
Grandad shook his head. "It's just wrong."
"So was it wrong for me to marry a woman from Malaysia? And it was wrong for us to be happy together for 50 years?"
Grandad looked at him, but didn't respond.
"This is not like you," Wong continued. "You're not a petty man. What's really going on?"
Grandad hesitated for a moment before slowly opening the drawer beneath the counter and pulling out an envelope. He looked at it for a moment.
"I received this 10 days ago," he said quietly, before proffering it to Wong.
It was unclear the next morning whether Grandad had left early to avoid Ethan or Ethan had risen late to miss his grandfather's departure.
Either way, when he did eventually emerge from his room, Ethan was relieved to find his mum alone in the kitchen, filling the sink for the washing up. "Let me do that," he insisted.
"I've got to do something until I go back to work," she answered with a smile.
"That's right - and what you've got to do is rest."
As he scrubbed the bowls, Ethan continued to fret over his grandfather's behaviour. The fact that he held some old-fashioned views wasn't surprising, but being callous enough to express them directly to Maya's face ... now that was totally out of character.
Simple mathematics guaranteed that Chan, the property developer, couldn't take over the building that housed Grandad's shop. So ...
"Mum," Ethan began hesitantly, "what's wrong with gung gung?"
The smiled faded from her face. "You've noticed?"
Ethan did no more than nod.
"I'm afraid he's had some bad news about an old friend, Sui-man."
Ethan had been waiting at the cha chaan teng for 25 minutes when his mobile rang. He snatched it up without checking the caller ID.
"Maya!" he exclaimed. However, his sense of nervous anticipation drained away the instant he recognised the voice on the other end of the line. "Oh ... Sam."
"Wow, that must be what it's like to call someone up and try to sell them insurance. Maybe you'll sound a little less disappointed when I tell you my news."
Ethan continued to scan the street. "Sorry. Yeah, tell me."
"You know the investor who lent us most of our start-up money? He wants to take up his option to buy a stake in shamefacebook."
Now Sam had his full attention. "Yeah?"
"He says that, given how popular the site has become, he's willing to make a substantial offer."
"What does he mean by substantial?"
"I don't know yet, but I can't wait to find out."
Ten minutes later, Maya found Ethan gazing into space and wondering whether "substantial" could possibly mean substantial enough to finally make his family financially secure.
"Sorry, I'm late but Dad called and ..." she began, before Ethan cut her short.
"Maya, before you say anything, there's something I've got to explain."
"No, listen, please. Grandad isn't himself at the moment, and now I know why. Mum's told me he got news from America that his oldest friend has died."
"The poor man," Maya muttered, tears welling in her eyes.
"Hey, hey, I know it's sad," Ethan told her, squeezing her hand. "But Mum did say it wasn't a huge surprise, he was in his 90s."
At this, Maya slowly shook her head before taking a deep breath to gather herself. "The thing is, Ethan, I've got more bad news for your Grandad ..."
"How is your girlfriend?" the elderly man asked matter-of-factly.
If he hadn't been dreading relaying what Maya had told him, Ethan would have been touched by Grandad's clearly genuine attempt at a reconciliation.
"She's fine, gung gung ... Well, no, actually, she's not. She's very upset."
Grandad looked up sharply from the ledger spread on the counter of his dingy paper-offerings shop.
"No, not at anything that was said," Ethan added hastily, "but at something she's ... found out." He hesitated. "Grandad, another property in your building has been put up for sale."
However, his grandfather didn't gasp or exhibit any signs of shock or surprise. Instead, he just quietly muttered to himself. "I knew it ..."
"But what is Mr Wong doing?" Ethan exploded. "He knows if Chan buys it, he can drive you out."
"It's not Mr Wong's shop, or his flat, that's being sold ...," he paused to look around, "... it's this place."
"What? But I thought you said your landlord would never sell."
"He wouldn't. I started working for him over 50 years ago. When he retired, he gave it to me to run and charged me a rent that didn't go up in 15 years. To him, it was much, much more than a business."
"So why ..." Ethan began, before realising his grandfather had used the past tense. "It was your old boss who's just died?"
Grandad nodded. "And now his sons must have decided to sell this old dump to get their hands on their rightful inheritance."
To be continued next week