Tools -> View Addresses -> Right-click an address -> Private Key; done. You have it.
And to obtain private keys of all the address, one need to follow this:
Wallet -> Private keys -> Export
You will be seeing all private keys. You can copy them or export them.
I think that you shouldn't do this at all. It is a great feature, no doubt , but you are compromising your safety when you see your privatekeys in your computer.
You should note down your seed in a piece of paper and forget about those Private keys forever.
The seed should be used only when you need to recover your funds because you can't access your wallet anymore (lost device for example)
Additionally, electrum is safe as long as you always download/update it from electrum.org website, there is no other.