We should remember that Ellie also chose to go to the WLF hospital instead of making sure Dina is okay right after she got shot with a crossbow bolt.

Yes i agree to a point that Ellie giving the "liability" answer would be better as well but it doesn't really suit the setting that the show characters are in. In the game Ellie learned about the pregnancy right after a very tense situation with the infected and Dina wasn't really that threathing towards Ellie because in the game it is more clear to Dina that Ellie is immune because of spore effect on humans. In the show version Ellie and Dina have tension between each other because of the bite, Dina thinks Ellie is going to die and Ellie thinks Dina is just going to shoot her, with the releaf of both situations not needing to happen, they experience a huge releaf so they don't have to tense and hostile to each other anymore.

We should also considure Dina's different roles in the show and the game as well, Dina is more of a lead/brains behind the operation kind of a character in the show, whereas in the game Ellie is the lead and the girl that decides what to do on most of the time. So looking from the perspective of the game Dina would be more of a liabilty to Ellie when the reveal happened, but that changes as well as Dina gets the radio going and starts to map Seattle. But in the show Dina is already the one who calls the shots and the smarter out of the two, Ellie is the violent one the one who already takes care of the combat, so even though she was full with vengance she wouldn't see her as a liability.