I discovered recently that besides the risqué nightclubs and Thai food eateries, Orchard Towers also houses a Vietnamese eatery on level four called "Thien Long". The lady who took my order was Vietnamese so I expected the dishes to be authentic and based on what I tried, they didn't fail.
For example, this $5 bowl of Vietnamese Pork Chop Noodles was a hefty portion of skinny rice noodles served at room temperature with lettuce, cucumber, mixed pickles, fresh herbs, fried shallots, scallion oil, groundnuts plus hot-off-the-grill pork.
Just ignore the radioactive shade of orange of the meat because it tasted fine. Obviously, it'd been marinated well and for a while, as it was flavourful.