<p>I believe those sentences do not change tense.</p>
<p>In the first sentence, running acts as a participle, not a verb. A participle is a verbal used as an adjective, thus no need for tense agreement.</p>
<p>I think the second one is all past tense.
I drew (past tense) my breath when the murderer entered (past tense) the room.</p>
<p>I could be wrong, someone please give advice if I am!</p>
<p>You answered the first question yourself--modifiers must be right next to the thing they are modifying. For 'referring' to work, the sentence would have to read: The word ceramics, referring to both the material and the product, comes from the Greek keramos, meaning "potter's clay."</p>