That's the thing about real combat situations, it doesn't matter if you are sober, drunk, ready, not ready, feeling good, sick, etc. He looks like he fought some one else and was taken down by security. One of the guys in the jersey turns around and rubs under his eye, looks like Dillon got a punch in on him and the other guy with the man bun is also a worker there. He's helping with the situation and he has a white towel in his pocket. It's usually what servers/bar people have on them at all times while working since they are constantly wiping something down from spilled drinks/etc. He also helped secure him with the other security and keep the area clear from other people.
Sport jitz has it benefits, but by itself it isn't complete in modern mma or street fighting situations. Everything changes when there is a hard floor/concrete and there are strikes being thrown. That's why it's best people cross train to be able to be ready for the other variables. Even training past just sport focused martial arts because real combat situations are very different.
I don't know the security's skill level but he seems to have been able to control Dillon at this moment, so I wouldn't be quick to assume Dillon can beat him because this situation the security had the upper hand and had Dillon stuck. It's just 1 security on him and not a group of security on him. Either way lots of security/bouncers train martial arts and a lot are actual fighters that compete or used to compete. Lots of UFC fighters were bouncers before fighting/training full-time.
I just don't think Dillon is good at any situation away from sport scenarios. From everything I've seen it doesn't seem like his comfort zone. Sport and real situations are very different, success in one doesn't mean success in the other and vice versa. Don Frye got KO by security/bodyguard in a hotel lobby before. Lots of situations like that happen in real life. Even Gaethje got tapped out by Nelks security when they were messing around. Some security have legit skills and a lot of their skills are more for real life combat situations and not so much sport fighting skills, even though a lot can do both and have done both as a career.