It took her a while to notice his unusual silence. Mikaela was too busy working up to her elbows in leaky piping.

Despite the dire situation, the relative ease of the fix allowed her to fall into an efficient rhythm; clamping off dripping lines, measuring and cutting tubing, and fitting in a harder bit of plastic to serve as a coupling under the clamps between old and new tubes.

Drying, deprived fuel lines quickly began to cycle once more, one after another. It would make a lot of fiddly integration for Optimus' repair systems, once he was properly on the mend, but it was better than not being repaired at all.

Mikaela tried to keep up a semi-steady stream of commentary as she went, mentioning when she was clamping or unclamping a line, so Optimus wouldn't be surprised. But the talk was bland and didn't really require any response unless the huge 'bot objected, so she wasn't surprised by any lack of any response. It was only when she pulled out with a grunt, legs cramping from kneeling down for so long, that the silence seemed to linger.

"Optimus? I've finished with your shoulder. I think I got it all?"

She paused, placing an alarmed hand on his armor after the moment stretched; relieved to still feel the vibrations running through him.

"...Optimus?"