Thanos, the deadmans switch bluff will likely give you the delay your looking for. But NO WAY would they not arrest you after that. I like the idea. Needs refinement.
"I forgot the combo" seems like reason for arrest to.

They are there to eliminate what they are told is a threat. Taking guns is
surely easiest. Taking the guy and family that may or may not know the combo to a possible stash eliminates the threat as well. Once taken, you still wont see those guns again for any one of a dozen possible reasons.
Nobody wants to accept stuff like this happening to "them". But, "thats just pride F'n with your head". Was there really any reason at ALL to take the little old lady's pistol from her? The orders are "NO FIREARMS".
Soldiers follow orders. Logic and common sense as
you see it has nothing to do with their
orders. "
NO firearms" is what they will do!
Marines and other military members here. Think back a little to your mindset on a mission. If you were told "NO FIREARMS". You KNOW you would
NOT have accepted exceptions. Thats what basic training is all about. To teach
every soldiers mind how to accept and excecute orders. NO EXCEPTIONS. You wouldnt have graduated if they werent
positive they got that message into your head.
Your only hope as a gun owner. GET OUT OF TOWN! If you cant do that, you'd better be DARN sure they see NO reason to even suspect for 1 second you might have a gun!