^^ Yeah he probably would have felt it. In that case Vader could just be seen reporting directly back to the Emperor (which he probably would have done in such an extreme scenario) who could allude to the fact that "he is already aware of the setback".

I always pictured such a scene as ending with Vader leaving Palpatine at some point and then hearing that the person who destroyed the DS was Luke Skywalker. Thus we'd get to see that pivotal moment onscreen leading to the events of ESB where he already knows of Luke. As it stands we are left to assume that between movies but it plays so nonchalantly that it seems a bit off in hindsight.

But realistically I don't know how well that would all jive with the Emperor/Vader scene in ESB. How could Vader get such important news so early but Palpatine apparently learns much later on?