"Calvin Made it - Lisa."

<<Why didn't they edit it or re shoot the scene?>>

I think probably the director wanted that perfect dawn shot. And didn't to do a retake. Probably by the time they were ready to shoot that again, they'd have lost the dawn sky as you see it in the background.

Now, they probably could, and maybe even should, have fixed in post. Looping in dialog is a common practice in movies and TV, when the live dialog recording is muffled or otherwise obscured in whichever way. There's a lot of things where there will be an isolated line or two that sounds "not right" or at least "different" from the rest of the scene. That's looping. So they could have easily gone in and had Dennis Quaid say "Calvin made it...Ethel!" and be done with it. It would have been nothing for them to do that, since Quaid probably had to loop other bits of dialog as well.

An even simpler idea would have to simply change the character name to Lisa, seeing as that's literally the only time in the movie (at least in it's finished form) her name is ever said. The only reason any of us would have a clue that her name isn't Lisa is the closing credits (well, except those who have seen the script or who were involved in making the movie). I wonder at what point the closing credits were created. I've heard it said that's actually an expensive process in film making so very rarely are they ever redone.

Another possibility is that nobody caught it at the time. Maybe everyone on the shoot was exhausted or had other things on their mind, and they thought "We got the shot", and that was the end of it. Nobody noticed, or maybe had the nerve to point out, that Quaid had said the wrong name, and they let it go. Or if they did, they figured since it's the only time her name is mentioned in the film, nobody would notice or care. They were probably thinking, "Yeah, like anyone ever reads the closing credits!". 

BUt yeah, I picked up on that years ago. Unfortunately, Lisa Maurer wasn't in very many movies. I thought she looked hot, especially in this one. I love the shot where she, Calvin, and the third technician, are in the control room, and Calvin says he's going to blow up the the pump "over some, some, some, DAMN FISH!", the look on her face, where she looks like she's about to punch both of them, is great. And I love all those shots of her sort of nibbling on her lips.