nearly losing those close to him made him protective&thats no different with you.Even if you are capable of defending yourself,Sonic wont care,he won't let you join in any missions with him.But if you're stubborn enough,he'll let you join only if you promise to stay by his side the whole time.If harm were to come to you, Sonic would get quiet & then quickly check for any physical harm on you.If it were to have happen on a mission with him,then forget about going to another one.He wont let you.