How to pass a signer to the instruction that will be executed by a clockwork thread

I get a signer privilege escalated error and I suspect that it is because I am incorrectly passing the signers to the executing thread instruction.

Here is roughly how MyContext looks like (including pda initialization):

pub struct MyContext<'info> {    #[account(        init,        seeds=[...],        bump=,        payer = creator,    )]    pub acc: Account<'info, MyAccount>,    #[account(mut)]    pub creator: Signer<'info>,    #[account(signer, address = thread.pubkey())]    pub thread: Account<'info, Thread>,}

This is how I invoke the associated MyContext instruction:

    const ix = await myProgram.methods        .myContextIx({...})        .accounts({            acc: acc,            creator: signer.publicKey,            thread: threadPubkey,        })        .instruction()    const thread_transaction = await threadProgram.methods        .threadCreate(            threadName,            {                programId: myProgram.programId,                accounts: ix.keys,                data: ix.data,            },            trigger        )        .accounts({            authority: signer.publicKey,            payer: signer.publicKey,            thread: threadPubkey,            systemProgram: anchor.web3.SystemProgram.programId,        })        .rpc();

So I am wondering how do I make a thread execute a designated instruction that requires another signer. In this case, both the thread and the creator account?

I can see from the thread_exec.rs source code, that the signer for the thread CPI instruction call is always going to be the thread account, so is it even possible to consider another signer?