Bmwman91 had a crack and drive a while, but as soon as he shut the engine off, it drained out. Vacuum kept the oil in.
As for no oil... I have heard of people driving quite a ways with no oil in various cars. Sometimes 45 minutes plus. The engine was trashed at that point though.
A few seconds with no oil, especially if it just had oil in it is not a problem really. After that, hard to say. On our motors there are two fears of no oil. First is the obvious bearing problem, our motor bearings are not held in place well and could spin easily, though I have not heard of it happening with any frequency. The only reason I know is from having seen the locks compared to other engines. The other problem we have is the chain tensioner. Oil helps control the chain, if it is flapping around because you need a new tensioner or the chain s worn, low oil could trigger a failure here.
Telling you how long to expect the motor to last without damage though is next to impossible. Once that light comes on, you should shut off the engine as soon as possible.