We're seeing exactly why players pressure officials. Pawson was about to blow up to give the free-kick for the foul by Dier but knew he'd have to send him off so changed his mind, he's then getting abused for stopping play for a head injury when Bournemouth are on the attack and even more so when Dier tripped Wilson in the area (he can't see the challenge so he can never give it). The moment Spurs gave him an excuse to send somebody off or give a penalty he was giving it and Son gave him that excuse.