He wasn't scared of the male mercenary but the female as she could kill Lucy before he could act, but the male was holding acting physically, so his reflexes won't be able to catch up to what Leo was about to do.
When he threw the pouch to them, he deliberately threw it at a place a little bit far from where the two mercenaries were standing, so one of them would have to go pick it up.
"Oops," Leo said making it sound as if he threw it that place by mistake.
'This boy is planning something' the male mercenary thought.
Giving Leo a threatening glare for the second time he said "One, go pick it up."
"But..."
"I know... I know what am doing. Go pick it up, I can handle him" the man interrupted her.
Both of them seemed to know that Leo was planning something, but they did not know that he could teleport. So the man was confident enough that he could kill Lucy if Leo tried to pull off any tricks.