The most important piece of feedback for a McKinsey, BCG et al networking event is to do nothing. You actually want to draw as little attention to yourself as possible. Networking events are really formats where consulting firms market themselves. There are obviously exceptions, but rarely is this going to be a moment for you to market yourself. For one, there is too much happening around you and you will almost never get an opportunity to dazzle anyone.
Your strategy should be one of reconnaissance, collective information, not embarrassing yourself and observing your competition in action.
A strategy of trying to prepare for every conceivable situation in the hope of impressing the attendees will never work and is not worth trying.
There will be a time to do this and it is not now. Better to collect some contact details and then aim to impress in a follow-up one-on-one discussion.