There are many things in larger context of grappling which can be done to uke who rolls out of ikkyo.
However, since Aikido is heavily shaped by its pacifist philosophy, the Aikido response to uke rolling out of ikkyo should not involve pursuing him, locking him down or otherwise punishing him. He's currently not attacking you, right?
So perhaps the response is actually about doing nothing. It's not a practical response, but it is an Aikido one.
Escapes has the wrong connotation I think. The technical term is "reverses". The attitude you are describing is incompatible with the situation where the attacker reverses with the intent to cause you harm.
Btw, there is a funny story about the second doshu and pacifism.