Vomiting in Halakhah IV

The following question arose in the comments to an earlier post, so I will begin with this true story (no names have been changed!) and proceed to the halakhic question and the answer:

I was taking the subway home and right before my stop to get off, a child vomited. I had my head in a Torah book but, well, you can't miss that sound. His mother was comforting and my stop was coming up in a few minutes. Was I obligated to stop learning (or switch cars, which is supposedly dangerous to do while the train is moving but everybody does it)? Why would I be obligated to stop learning?

The Torah prohibits learning or even thinking about Torah in an area where there is excrement. This is a matter of respect for the Torah. Extending this aspect of respect, the rabbis prohibited learning in the presence of urine as well. The Arukh Ha-Shulhan (Orah Hayim 76:21) writes that this extends to anything that is disgusting, such as vomit. Torah study (and prayer) should be done in clean areas as a matter of respect. However, the Mishnah Berurah (76:20) quotes R. Akiva Eiger (I couldn't find it, but I didn't look too hard) who explicitly states that this rule does not apply to vomit. So there I was, on a train with vomit, thinking about this dispute not knowing whether or not I was even allowed to be thinking about it. Then my stop came.

I later asked R. Mordechai Marcus, a local adam gadol, who told me to be lenient. While he is not generally known for being strict, I took this in the sense of R. Joseph B. Soloveitchik's general opposition to stringencies that prevent Torah study.

UPDATE: A reader e-mailed me, and I confirmed, that R. Hershel Schachter is of the view that one may not learn in the presence of vomit. He discusses it in this lecture on this week's Torah portion (from 2001, about 1 hour 7 minutes into the lecture).