I'm a bit confused... (older Dahlia.)

[Dogg Thang]

Dahlia saying she'll get Cheryl when she doesn't even know yet who is calling makes it exceptionally unlikely that she means she's going to hop in her car, drive to the clinic and interrupt the session just to tell her that someone is on the phone. That's a leap.

[AuraTwilight]

It looks like the two of them walked there, and considering the vague hints that Michelle and Dahlia were taking Harry further and further from Cheryl, and how she's not actually in a literal lighthouse, makes me doubt that the trip is as long as you're thinking. It's also not rare for therapy sessions to take recesses without stopping for the day, so it's not like Dahlia would've just had to burst in and pull her out.

[Dogg Thang]

Mode of transport really isn't the issue. The words Dahlia uses and how she says them really only works if Cheryl is in the same living space as Dahlia when the call is made. She doesn't ask who is calling, she doesn't ask if it's important. It's a very casual - you want me to get her - like all Dahlia has to do is shout to Cheryl. She's not going to ask that without knowing who it is, put down the receiver and walk to where Cheryl is having a therapy session on the off chance she's having a break. Even if the clinic was right across the road from where they lived, that wouldn't work.

You seem to see that differently so I'll leave it at that. This is just how I interpret it and, for me, it requires way more leaps for that to work than to simply take it that the Dahlia we hear is not the real Dahlia. But Silent Hill is always open to interpretation - that's what's fun about it, I guess.

[AuraTwilight]

Mode of transport really isn't the issue. The words Dahlia uses and how she says them really only works if Cheryl is in the same living space as Dahlia when the call is made. She doesn't ask who is calling, she doesn't ask if it's important. It's a very casual - you want me to get her - like all Dahlia has to do is shout to Cheryl. She's not going to ask that without knowing who it is, put down the receiver and walk to where Cheryl is having a therapy session on the off chance she's having a break. Even if the clinic was right across the road from where they lived, that wouldn't work.

She does ask "Who's calling? You want me to get her for you?"