I think it's a good question. There are a lot of trade-offs, and people with expertise in different spaces who would likely give competing advice.Genuine question: Which organisation is actually the most expert in station crowd control (at a main line terminal such as Euston so, for example, London Underground or Hong Kong metro not really applicable)?
Anybody with Platform-Train Interface expertise would likely push very hard for the numbers of people on the platform to be kept to a minimum. People experienced in dealing with surges in wider spaces might suggest getting people off the concourse as quickly as possible. Anybody who was licensing a club or festival to be honest might well throw their hands up in despair and declare that you needed people on the external doors limiting station capacity to 1000. People designing the pavements would be terrified that people queuing outside would end up under a bus.
I honestly don't know who has the most expertise or the most joined-up teams. ORR as a regulator are mostly focused on getting signed-off plans which indicate that NR have engaged the relevant expertise, and I suspect that most of the heavy-lifting is being done by a combination of NR and the RSSB. Whether they have the expertise in place or not I don't know.
Personally I just don't think there's a good way to completely eliminate risk in this scenario, and I suspect that a culture in the railways of expecting to completely eliminating risk isn't helping. It seems like we may be ending up with arbitrary actions put in place to mollify the people who shouted loudest and most recently.
I am not any kind of safety officer though, and would absolutely hate to have the job, so I'm reluctant to start saying that one thing or another is wrong, short of saying that whatever is currently happening doesn't seem sustainable.