The local sheriff could have knocked on the door and asked to see the weapons Howell was alleged to have.
Howell would mostly likely have invited him in to see them. And Howell would have probably given them to the sheriff if asked.
This isn't idle speculation: it's what Howell did on at least one previous occasion. The firearms were subsequently returned without incident.
Once the agents were killed, there was no turning back. This should NOT have ended with an inferno.