In cerseis and tyrions conversation she states the only thing that's important to her is preserving her family and tyrion finds out that she's pregnant. Tyrion also states that he would of done anything for her children.
Tyrion may not of made an explicit pact with her but cersei might of purposefully put seeds of doubt in him because he knows if dani wins and kills cersei he will be responsible for the last of his nieces and nephews death.
This could explain why tyrion was secretly looking at danis chambers because he's realizing he's looking influence with dani so we might possibly get a tyrion betrayal for cersei.
On a side note how ironic is it out of all of cerseis pregnancies not one of her children came out deformed or handicapped in the slightest. It would be ironic if cerseis last child is a mutant and she still loves it.
Tyrion may not of made an explicit pact with her but cersei might of purposefully put seeds of doubt in him because he knows if dani wins and kills cersei he will be responsible for the last of his nieces and nephews death.
This could explain why tyrion was secretly looking at danis chambers because he's realizing he's looking influence with dani so we might possibly get a tyrion betrayal for cersei.
On a side note how ironic is it out of all of cerseis pregnancies not one of her children came out deformed or handicapped in the slightest. It would be ironic if cerseis last child is a mutant and she still loves it.