Trial of sekehmas - add confirmation before leaving floor

I just ran enough trial of sekehmas to get a Last Flame and one of the biggest issues I had was a few times I accidentally clicked the next trial portal before purchasing anything from the vendor.

Either make it so you can buy items afterwards or add a confirmation or something. Why does it matter either way? It's not like I could back track to the vendor. I should be able to use the vendor and chests until I actually leave the room...