That is a huge guess. After 10 officers are shot I doubt the SWAT team was in a guessing mood.
> he wasn't going to get the opportunity to leave.
This is perhaps the most commonly fallacy I have read in this thread. Immobility does not immediately equivocate to either a reduction or increase in potential threat. The guys on the ground have to make that determination based upon the evidence available in the moment. After 10 officers were shot I am sure the suspect vocalizing additional threats likely didn't help the SWAT team believe the risk was diminishing.