What are the visa implications for repeated overland crossings into Thailand and how can we prepare for emergencies while rock climbing?

Seeking advice regarding overland crossings.My partner and I are traveling around SEA and get the 30 day visa exemption every time we come into Thailand. My partner tried to cross into Thailand by land for the 3rd time in a year (not consecutively) and was denied access at the border (he had to go back to Siem Reap and FLY into Bangkok instead). We both plan to rock climb Thakek, Laos for 2 months. If a medical emergency happens, the quickest way to Bangkok is to cross the border to Nakhom Phanom (takes 40 mins) and fly to Bangkok. Now that we've learned we cannot cross by land again, I'm scared for our time rock climbing. In case of medical emergency, we would have to take a 7 hour bus ride to Vientiane and fly from there to Bangkok. That is a scary thought if a true emergency happens. Has anyone had experience with this rule or getting around it? Any advice appreciated!