personally and professionally speaking
the amount of time your talking about here is a second or two because once the operator realizes the lift is going over it only takes a second to reach over and push the button or pull the latch and thats it.

in more cases than not the operator has always gotten injured or killed jumping off a lift trying to escape it if it turns over or goes off a dock, if he does not then he is one lucky person.

if there is that much risk of the lift going over the edge i would suggest putting something place to prevent that first before relying on human intuition and ability or making your own accessments and circumventing OSHA regulations.