I agree with all the sentiments trying to help and at the same time not adding to the nerves. At one point I bought DD a book of questions on Amazon, decided not to take them too seriously and of course none have come up in either of her first two interviews, but it is good practice for thinking on your feet.
I also bought a star shaped key ring to say how proud I was of DD getting this far which goes to interviews with her. Tell your DC you know they have it in them to be great doctors, just before there interview and now is their chance to let the medical school know too.
From what I have gleaned Liverpool do a maths station it is said to be fairly simple (or rather not A level for those of us whose DC didn't carry on with maths); there is also a video to watch before hand as a sort of pre brief.
Perhaps my DD doing AS level drama has helped and also applying for deferred so Plan B sort of in place (results are not a forgone conclusion!).
The medical schools want to know our DC will suit the course, can self direct and learn, can work as a team and listen to opposing views, will not make judgements and are happy to admit to having faults.
Interestingly both my DD and another on TSR (post offers) admitted to reading something and coming to a simple conclusion at Hyms, then walked into the station to discover their mistake - clearly both recovered and whether it showed or not it wasn't disastrous. Won't say more but poster on TSR gives a little more away. I suspect it may have been deliberate, but maybe not.
Weirdly classmate of DDs had an odd experience at UEA, but hasn't divulged - so DD went into that one very nervous and expecting something strange to happen, but had nothing to report.
I found open day at Liverpool very friendly and lovely admissions lady who clearly was very proud of her students, I think I have said before, we asked her about deferred entry and whether to put something in writing about plans - she said 'just let us know on UCAS and then have a lovely year off, relax and enjoy it, you deserve it'.
March does feel like a long time to wait, and to keep focussing on school work is tough. Keep positive, just getting this far is a huge achievement, 40/50% ish chance post interview for many!