要 has two meanings:
1) want
2) should
here, we use the second meaning: should
不要: shouldn't
不要放: shouldn't 放
another example:
I want to go there. (我 想/要 去那里。)(because there is funny, if I dont go there, nothing serious will happen)
in this case, 要 and 想 are the same but 要 is stronger
I should go there. (我 要 去那里。)(because I work there, if I dont go there, something serious will happen)