If everything goes smooth, escrow would not need to hold script:

1. I send bitcoins to escrow.
2. You send script to me. I confirm it is OK to escrow.
3. Escrow sends bitcoins to you.

If transaction would not go fine:

1. I send bitcoins to escrow.
2. You send script to me.
3. I "do not like" what you sent.
4. You send script to escrow.
5. Escrow takes a look and decides, either he refunds me or he sends bitcoins to you.

I think the the point of using escrow services for software related transactions is to try to avoid him having (free) access to what I am paying for


Edited: I messed up step 3, I fix it