This happened about 5 minutes ago. I launched 2 missions to the Mun: The first vehicle was to orbit the Mun at 60 (ish) km, the second one was to land and after some fun with EVA, rendezvous with the first one to transfer the crew and return to Kerbin. After the extravehicular activities I decided to use the ascend module in mech-jeb, cause I was to lazy to do it myself, but I inputted the wrong inclination. I realized it was wrong, I continued to circularize, then made corrections to the orbit. I finally got within 500 m of the first vehicle but the fuel ran out and the RCS block I was using didn't have forward and backward thrust so I switched to the return vehicle and got close to the lander but it was not enough. I switched back to the lander and went EVA and by the time it was the last member of the crew's turn to transfer, I realized that the return vehicle was going to crash because of the extreme maneuvers I did. This is where I freaked out. I thought - "What if there's not enough thrust to gain the vertical speed needed to avoid crashing? Still have a few minutes left, though. Might try to save that last kerbal." When I pointed my view toward the vehicle I saw it was spinning and thought there was no time to switch again and stop it, so I continued to approach it, crashed into it a few times but finally got in. I started a burn straight up and when the vertical speed indicator reached 0, the altemeter said 2,000 meters but I was so close to the ground that even Jeb started to freak out. That was one of the closest calls I've had in KSP. I was so excited after the successful mission that I almost broke my keyboard.