If you choose to get out early, the liquidity of many corporate bonds is far superior to the liquidity of almost any CD and that means better bids when you do go to unwind from your position. Generally, very little. That seems fairly consistent with my observations. That seemed wide to me. It might be for a bond that isn't very actively traded so there's not a big market bidding up the bid price.
Many people see bids and offers in the newspaper.
So, the large spread as exhibited by this question can be due to any number of reasons. Not all bonds have calls on them. Event risk is a risk of a downgrading in your bond as a result of bankruptcy or merger or takeover or some unforeseen event. Sometimes event risk can work for you. In the case of Long Island Lighting Company, which had been facing financial problems, the State of New York moved in and became its partner resulting in the bond being upgraded strongly.