> Then she remembered; Paul and Minta and Andrew had not come back. She
> summoned before her again the little group on the terrace in front of
> the hall door, standing looking up into the sky. Andrew had his net
> and basket. That meant he was going to catch crabs and things. That
> meant he would climb out on to a rock; he would be cut off. Or coming
> back single file on one of those little paths above the cliff one of
> them might slip. **He would roll and then crash**. It was growing
> quite dark.<br/> (Virginia Woolf, To the Lighthouse)

[He would roll and then crash] is at the past reference time and when we foreshift this it would be [He will roll and then crash]. 

If the original sentence were [He would have rolled and then crashed], it would not a irrealis, but just a backshifted form from [He would roll and then crash]. And it puts more psychological distance from the probability. Is this right?