Eric has very sharp senses - a special trait bestowed on at least one of those of the imperial blood.
He can hear even the faintest of sounds, smell the weakest of scents, and feel any presence. Or at least, he can under a certain condition that is hard to meet in his case - a condition that highly depends on the user himself. Wielding this ability requires strong determination, unbending will power and a fixity of purpose, which were everything he lacked before he met Seraphine.
Now, Eric has them - he has found a reason to fight at last.
That's why he managed to escape the backstage and go after Clifford. He took down every obstacle he confronted on the way. Whether it were the men who oppressed him earlier or the guards around the area, he stopped at nothing. He only continued to use the dagger that he stole from one of them and slash his way out of there.
