Flip BTC in what way?
In percentage terms as seen on the coinmarketcap site, BNB is still ahead of ETH with the respective percentages of the coin currently being BNB 12% and ETH 5.5%.
This means that BNB has increased faster than ETH.
So far there has been no altcoin that can beat BTC and almost all the top altcoins are very influential on BTC.
In terms of the percentage increase in price everything won't be exactly the same, you can see a nearly 20% increase in BNB over the past week, but that's still not that great when you look at Ethereum's only 5% increase in price over the past week , but quantitatively the price difference is still very far away and this is still being held by Ethereum at this time.