Party discipline is much stronger in the UK Parliament than it is in our Congress. The parties have a lot more tools to keep their members in line, and defections are rare, particularly in no confidence votes like this one. There hasn’t been a successful no-confidence vote since 1979, and the major parties voted entirely along party lines.
I’ve been in Canada a couple of decades so I am more aware than your average Yank.
Still things are razor thin so it wouldn’t take much.