I think he actually made the decision to take the shots rather than clinching because it was probably the better option, he could barely keep his guard up, imagine trying to hold a physically stronger fighter with a torn bicep. He had no choice but to take the shots. His team did the right thing letting him fight on he took some heavy shots but he never seemed close to being dropped.
Derevyanchenko is the unluckiest fighter in the sport in my opinion, he's usurped Matt Korobov of that position these last couple of years. The dude is very talented and tough as nails, he's never had the house behind him, so he gets no breaks. Now he's old and campaigning at a weight where he is a small guy with limited power but he still manages to buzz his opponents. He's right up there with the best fighters I've seen that never got their hands on an alphabet strap.