Meaning of 滾水 as Cantonese idiom 滾水 (Cantonese gwan2 seoi2) is used (often in restaurant kitchens) as a warning.
It literally means &quot;boiling water&quot;, but I think it indicates that something potentially dangerous or fragile will be coming by immediately.
Does it mean:

Get out of the way (make room for me to pass).
Don't move (I'll steer around you, but you must be predictable).
Something else?

The first two require quite different responses, so it's important to know which is expected.
Speed and efficiency is prized in Cantonese (particularly Hong Kong’s) culture.
If someone tells you he has got 滾水, it literally means that he needs you to make way for him, unless you wish to get scalded while he crashes into you.
This term is commonly used by waiters in Hong Kong eateries, who serve hot food to cramped dining areas.
Nonetheless, it can be used figuratively, even when people aren’t transporting scalding hot items around.
If there are workers pushing boxes of goods across a shopping mall, they might probably shout “滚水!”, so that the crowds can immediately recognise their presence and get out of the way.