A delegatecall'ed function executes inside of the delegatecaller contract's own memory & storage context.
But I'm wondering whether the following is in any way possible (i.e. if certain access modifiers are used):
EOA msg.sender calls contractA.method(), contractA.method() delegatecalls to contractB.(), contractB.method() runs. (Somehow?) ContractB's 'mapping (address => bool) approve;' is updated to include msg.sender[true].