Yes in principle you have to go in person or with agency on last day, and leave the Country by midnight of same day. Note some paperworks needs to be prepared in advance. You can ask for 7 days extension paying 1900 THB, this time is given to prepare luggage or organise departure but your visa and WP will be Void already
Ao Nang beach dogs are the most infamous in the Kingdom, not sure why but there have been several attacks expecially to kids in the past
https://www.thephuketnews.com/dog-bites-south-african-boy-at-ao-nang-beach-78048.php
https://www.thephuketnews.com/finnish-boy-5-attacked-by-stray-dogs-at-ao-nang-krabi-70465.php
https://www.pattayamail.com/thailandnews/stray-dogs-on-ao-nang-beach-in-krabi-targeted-after-attacks-on-tourists-401849
...and others
"He reportedly claimed he found the gun and the ammunition in a plastic box in front of an unnamed go-go bar, so he just decided to keep it"
Yah, yah..
https://www.google.com/maps/@12.9828895,100.9239095,3a,15y,173.84h,81.11t/data=!3m6!1e1!3m4!1sK6915HHAXjTIO7gdknLQLg!2e0!7i16384!8i8192
And with the grass all around could not even see. RIP
Can't be that one is boarding with these not be sure to be caught. May be miscommunication between Israeli and Thai secret service and the info was not passed over to the airport. We'll not be able to find out the matter will likely be handled between Embassies