The death ended weeks of speculation and teasing on-air promotions from the Seven Network, with the identity of the character kept secret since filming in September.
Ventoura told the Herald Sun that keeping details of the event secret was difficult.
"It was really important that we kept it on the down-low because of the impact from the shock of it," she said.
"Literally it comes from nowhere - it is such a shock and if it was ruined, it would have been such a shame."
"So we were trying really hard to protect the viewers."
The shock death was the first in three seasons of Rafters, and marks the second major cast departure since Jessica McNamee left the series earlier this year.
Ventoura described the confronting scenes in which her character had a car accident on her way to a romantic rendezvous with her husband Ben Rafter (Hugh Sheridan), as difficult.
"The mood on set (during filming of the episode) was very sombre, very intense anyway - and then added to that was the fact we couldn't go home and share it with our friends, 'My God, you'll never guess the day I had at work'."
The 31-year-old advised producers last year that she did not intend on renewing her contract with the series beyond the current third season. The move gave writers ample time to write her out of the hit drama, though she did not have a say on how she would be written out of the show.
"But I trusted implicitly that (series producer) Jo Porter and the writers would do it the best way possible,”
"And they really have. I feel really humble that they've trusted me and Hugh with this storyline, because it is huge."
It is believed the original cast members had standard three year contracts with the series, with several names including Jessica Marais highlighted as potential stars to leave the hit drama. However, filming began on season four last week and it is expected that all remaining central cast members will return.
Ventoura has since relocated to the US and has been doing the audition circuit.
"I've had a couple of auditions. But you've got to start from scratch and you're very much a tiny fish in a huge pond here. It's an adjustment."
Next week's episode, entitled 'Rest In Peace', will see Ventoura's character Melissa put to rest.
Media Spy discussion: Packed to the Rafters